CH502048A - Photochemical method for lithographic pla - tes and electrical circuits - Google Patents

Abstract

Method for producing an image by exposing a two layer element to electromagnetic radiation. The first layer is metallic and may be silver, nickel, copper, iron, columbium, lead, aluminium, zinc, chromium, or mixtures of these. The second layer consists of at least one of the following : halogen, sulphur, arsenic, selenium, tellurium or thallium. The element is capable of reacting at the interface with the metal so that in the exposed areas the second layer becomes separated from the first. Metal halides, sulphides, arsenides, selenides, tellurides may be used pref. arsenic tri- or penta-sulphide. The exposed areas may be removed by physical, mechanical or chemical means. Used for making lithographic plates, printed electrical circuits, resistances or condensers.

Description

       

  
 



   Process for manufacturing an object by photochemical means, in particular a printed electrical circuit or a lithographic plate
 The present invention relates to a method of manufacturing an object by photochemical means which is characterized in that one uses an element having a metallic layer of which one of the faces is in contact with a second layer of a material. inorganic comprising at least one of the following chemical elements:

   a halogen, sulfur, arsenic, selenium, tellurium, thallium, in that part of this assembly formed by the two different layers is subjected to radiation, so as to form an interaction product in said layers and in that the summer lying thus irradiated is subjected to a finishing operation. 



   The subject of the invention is also an element for implementing the method which is characterized in that it has a metallic layer, one of the faces of which is in contact with a layer of an inorganic material comprising at least one of the following chemical elements: halogen, sulfur, arsenic, selenium, tellurium, thallium, this element being capable of forming an interaction product when subjected to radiation. 



   Finally, the invention also relates to the object obtained by the process.  Such an object can be a printed electrical circuit or a lithographic plate. 



   The drawing represents, by way of example, several embodiments of the process, of elements for its implementation and of the object obtained by the process:
 Fig.  1 is a perspective view of an element sensitive to radiation according to a first embodiment and upon its selective and discontinuous exposure to incident electromagnetic radiation. 



   Fig.  2 is a schematic sectional view of this element. 



   Fig.  3 is a view similar to FIG.  2, but representing the sensitive element after its exposure to electromagnetic radiation. 



   Fig.  4 is a view similar to FIG.  3, but representing the sensitive element after removal of the product formed under the effect of the inter-reaction between the metallic layer and the outer layer, produced by the radiation. 



   Fig.  5 is a view similar to FIG.  4 but showing the sensing element after removal of the remaining unreacted parts of the top layer. 



   Fig.  6 is a schematic view of a device for practicing the present method. 



   Fig.  7 is a perspective view of a finished article. 



   Fig.  8 is a view similar to FIG.  7, but representing a variant of the finished object. 



   Fig.  9 is a schematic perspective view of a multi-layered sensitive element according to another embodiment of the invention and showing greatly exaggerated with respect to its thickness
The element during the process of exposure to electromagnetic radiation.  this through an appropriate mask or screen. 



   Fig.  10 is a schematic sectional view of the arrangement according to FIG.  9. 



   Fig.    11 is a view similar to FIG.  10, but showing a multi-layered sensitive element after exposure to incident electromagnetic radiation. 



   Fig.  12 is a perspective view of an example of a finished article obtained from a sensitive element with several layers according to FIG.  9, this after exposure to electromagnetic radiation and removal of the interaction product caused by the radiation, in accordance with another embodiment of the present invention. 



   Fig.  13 is a sectional view of the object according to FIG.  12. 



   Fig.  14 is a schematic perspective view of another embodiment of a finished object obtained from the object shown in FIG.  12, this by performing an additional operation in the method, and according to another embodiment of the invention. 



   Fig.  15 is a sectional view of the object shown in FIG.  14. 



   Fig.  16 is a schematic perspective view of a variant of the finished object. 



   Fig.  17 is a schematic sectional view of another embodiment of the invention. 



   Fig.  18 is a schematic sectional view of an object obtained by the method according to FIG.  17. 



   Fig.  19 is a schematic view of an example of an arrangement for obtaining an electrical component, such as a resistor of predetermined value, this according to another embodiment of the invention. 



   Fig.  20 is a schematic sectional view of one embodiment of the sensitive element, this element being intended for use in an arrangement as shown in FIG.  19. 



   Fig.  21 is a view similar to FIG.  20, but showing the sensitive element after its exposure to electromagnetic radiation. 



   Fig.  22 is a view similar to FIG.  20, but showing a variation of the radiation sensitive element. 



   Fig.  23 is a view similar to FIG.  22, but showing a sensitive element after its exposure to incident electromagnetic radiation. 



   Fig.  24 is a schematic view of a device for obtaining an electrical component such as a capacitor having a predetermined capacitance. 



   Fig.  25 is a sectional view of part of a sensing element for use in the arrangement shown in FIG.  24. 



   Fig.  26 is a view similar to FIG.  25 but representing the sensitive element after its exposure to electromagnetic radiation. 



   Fig.  27 is a perspective view of a variant of the sensitive element incorporated in the arrangement according to FIG.  24. 



   Fig.  28 is a sectional view of this element. 



   Fig.  29 is a sectional view thereof after exposure to electromagnetic radiation. 



   Fig.  30 is a schematic perspective view of a sensitive element intended to obtain an electrical circuit using an embodiment of the method according to the invention. 



   Fig.  31 is a schematic perspective view of the element according to FIG.  30, but showing a face not visible in FIG.  30. 



   Fig.  32 is a schematic view of the circuit obtained using the element according to FIGS.  30 and 31 and shown using conventional electrical symbols. 



   Fig.  33 is a schematic perspective view of an integrated electric circuit obtained according to one embodiment of the method according to the invention. 



   Fig.  34 is a schematic sectional view of a sensitive element and upon its discrete and selective exposure to electromagnetic radiation such as light. 



   Fig.  35 is a view similar to FIG.  34, but representing the element after its exposure to incident electromagnetic radiation. 



   Fig.  36 is a schematic sectional view illustrating an operation of one embodiment of the method, which operation consists in removing discontinuous parts of the outer layer of the sensitive element, parts which correspond to the element areas which have been discussed above. to electromagnetic radiation. 



   Fig.  37 is a view similar to FIG.  36, but representing the sensitive element after removal of certain parts of the outer layer. 



   Fig.  38 is a schematic sectional view of an arrangement for electrically plating those areas of the metal layer which have been uncovered by removing portions of the outer layer. 



   Figs.  39 and 40 are schematic sectional views of a sensitive element after electrical plating where it has received a thin layer and a thick layer respectively. 



   Fig.  41 is a view similar to FIG.  39 but showing item 39 on second exposure to electromagnetic radiation. 



   Fig.  42 is a view similar to FIG.  41, but showing the element after removing the remaining parts of the outer layer, this after the second exposure to electromagnetic radiation according to fig. 



  41. 



   Fig.  43 is a view similar to FIG.  42, but showing the results obtained by a second exposure to electromagnetic radiation of sufficient duration and intensity to consume in depth any thickness of metal from the metallic layer to the areas remaining covered by parts of the outer layer which have been previously submitted to such a second exposure. 



   Fig.  44 is a schematic view of a device for the electrochemical or erosion removal of areas of the metal layer which have been discovered as a result of the selective and discontinuous removal of portions of the outer layer. 



   Fig.  45 is a first embodiment of an object obtained after erosion of the parts of the metal layer which have been discovered by the outer layer. 



   Fig.  46 is an object according to FIG.  45 in which the remaining parts of the outer layer have been removed. 



   Fig.  47 is a view similar to FIG.  45, but showing the results obtained after complete erosion, using the device according to FIG.  44, parts of the metal layer which have been discovered. 

 

   Fig.  48 is a view similar to FIG.  47 but showing the object after removing the remaining parts of the outer layer. 



   Fig.  49 is a schematic view similar to FIG.  34, but showing a sensitive element upon its selective and discontinuous exposure to electromagnetic radiation impinging on the metal layer side of the element. 



   Fig.  50 is a view similar to FIG.  49, but showing the sensitive element after exposure to incident electromagnetic radiation. 



   Fig.  51 is a view similar to FIG.  50, but showing the sensitive element after removal of the products resulting from the inter-reaction between the constituents which is caused by the radiation.   



   Fig.  52 is a view similar to FIG.  51, but showing the sensitive element after electrically plating the remaining parts of the metal layer. 



   Fig.  53 is a view similar to FIG.  52, but showing the element of FIG.  52 during a second exposure to electromagnetic radiation in order to obtain another structure of the finished object. 



   Fig.  54 is a schematic sectional view of the object obtained after the second exposure according to FIG.  53. 



   Fig.  55 is a schematic sectional view of another object. 



   Fig.  56 is a schematic sectional view of an element sensitive to electromagnetic radiation in a predetermined pattern. 



   Fig.  57 is a schematic sectional view of the element according to FIG.  56 after exposure to electromagnetic radiation. 



   Fig.  58 is a schematic sectional view of the element according to FIG.  57 during the process of removing those parts of the outer layer which correspond to the areas which have been previously exposed to electromagnetic radiation. 



   Fig.  59 is a schematic sectional view of the sensing element stripped during the process of heat exposure. 



   Fig.  60 is a schematic sectional view of a first embodiment of a finished article. 



   Fig.  61 is a view similar to FIG.  60, but showing a variant of the finished article. 



   Fig.  62 is a schematic view similar to FIG.  56, but showing a variant of the structure. 



   Fig.  63 is a schematic sectional view of a finished article obtained using a sensitive element according to FIG.  62. 



   Fig.  64 is a schematic perspective view of a typical element sensitive to radiation, this in the process of exposure to electromagnetic radiation occurring in a pattern determined to obtain, for example, a printed electrical circuit or the like as a object finished. 



   Fig.  65 is a schematic perspective view of a finished object, such as a printed electrical circuit, obtained using the device according to FIG.  64. 



   Fig.  66 is a schematic sectional view of an embodiment of a sensitive element, this during the process of selective and discontinuous exposure to electromagnetic radiation. 



   Fig.  67 is a view similar to FIG.  66, but representing the element after selective and discontinuous exposure to electromagnetic radiation. 



   Fig.  68 is a view similar to FIG.  67, but
 showing an intermediate step according to another embodiment of the method. 



   Fig.  69 is a view similar to FIG.  68, but showing a subsequent step according to another embodiment of the method. 



   Fig.  70 illustrates a subsequent step according to another embodiment of the method. 



   Fig.  71 is a schematic sectional view of a
 variant of a step according to another embodiment. 



   Fig.  72 is a view similar to FIG.  71, but
 illustrating a subsequent step of briefly exposing the element uniformly to electromagnetic radiation. 



   Fig.  73 is a view similar to FIG.  72, but showing the results obtained by such a second exposure. 



   Fig.  74 illustrates a subsequent step in another embodiment of the method. 



   Fig.  75 is a schematic sectional view of another embodiment of the radiation sensitive element.  this during its selective and discontinuous exposure to electromagnetic radiation. 



   Fig.  76 is a view similar to FIG.  75, but showing the element sensitive to radiation, then. brief exposure to electromagnetic radiation. 



   Fig.  77 is a view similar to FIG.  76, but showing the results obtained by such exposure to electromagnetic radiation. 



   Fig.  78 illustrates a subsequent step in another embodiment of the method. 



   Fig.  79 schematically illustrates the object obtained by the method according to FIGS.  75-78. 



   Fig.  80 is a schematic sectional view of an element sensitive to radiation, during the process of selective and discontinuous exposure to radiation. 



   Fig.  81 is a schematic view of a lithographic plate or the like obtained using an element according to FIG.  80. 



   Fig.  82 is a schematic sectional representation of a variant of the element according to FIG.  80, this during selective and discreet exposure to electromagnetic radiation. 



   Fig.  83 is a lithographic plate or the like obtained using a sensitive element according to FIG.  82. 



   Fig.  84 is a schematic sectional view of another variation of a sensitive element during the process of selective and discontinuous exposure to electromagnetic radiation. 



   Fig.  85 is a schematic view of the sensitive element according to FIG.  84 after selective and discontinuous exposure to electromagnetic radiation, this to obtain an offset lithographic plate or the like. 



   Fig.  86 is a schematic view of a variant of the offset lithographic plate or the like, obtained with the aid of the sensitive element of FIG.  84. 



   Fig.  87 is a schematic perspective view of an element sensitive to electromagnetic radiation during the process of selective and discontinuous exposure to electromagnetic radiation, through a suitable mask. 



   Fig.  88 is a schematic perspective view of an element sensitive to electromagnetic radiation, this by electromagnetic radiation projected in the form of an image on the element. 



   Fig.  89 is a schematic view of a device using an element sensitive to electromagnetic radiation constituted by a beam of energy in a vacuum, such as a beam of electrpns. 



   Fig.  90 is a view of a device similar to the device according to FIG.  89, but showing the sensing element arranged outside the container containing the source of the electron beam. 



   Fig.  91 is a view of a device similar to the device according to FIG.  90, but in which the radiation sensitive element is in the form of an elongated and bendable member. 



   Fig.  92 is a schematic representation of an element sensitive to electromagnetic radiation in the process of exposure to electromagnetic radiation intended to sweep the surface of the element in a predetermined pattern. 



   Figs.  93 and 94 are schematic sectional views of a part of the element sensitive to electromagnetic radiation, after exposure to the radiation. 



   Figs.  9S and 96 are schematic views of alternative elements sensitive to electromagnetic radiation, before and after exposure to electromagnetic radiation. 



   The drawing, and more particularly fig.  1 and 2 thereof show a member 10 sensitive to radiation.  This element comprises a flexible substrate, a base or a support 12, consisting for example of paper, cardboard, plastic or the like, this substrate being covered with a metallic layer 14 consisting of a thin layer or a metal film or in metals, the thickness of which may correspond to a layer consisting of a few atoms or a few angstroms. 



  The metal layer is deposited on the base 12 by any conventional means known to those skilled in the art, such as bonding thereto, electrolytic or non-electrical plating, deposition in the form of vapor, emission of cathode particles, etc.  By metallic layer is meant a layer containing at least one metal, either alone or alloyed with another metal or with other metals, or combined or mixed with an element.  The metallic layer 14 can thus comprise one of the common metals such as silver, copper, colom bium, lead, iron, aluminum, chromium, nickel, etc. 



   On the metal layer 14 is deposited an adherent layer or outer layer 16 of a material capable, when exposed to electromagnetic radiation to interact with the metal or with the metals of the metal layer 14 to form therewith. ci an inter-reaction product or inter-reaction products whose chemical compositions and physical characteristics are different from those of the constituents.  The outer layer 16 is also thin, its thickness preferably being on the order of a few atoms or a few angstroms, and it is shown in solid form although it may be in the form of a liquid phase or a vapor phase. 

  The use of an outer layer 16 of materials reacting to radiation and in the form of vapor is particularly indicated since this greatly simplifies the processing of the sensitive element to obtain the finished object provided with an image or a a metallic pattern disposed on a flexible or pliable substrate or base, as will be described in detail later. 



   The material constituting the outer layer 16 may belong to a group of ternary materials including arsenic, sulfur or bismuth, for example.  The material constituting the outer layer 16 may alternatively belong to a group of binary materials such as a halide, such as an iodide, a sulfide, an arsenide, a selenide, or a metal tellurium, arsenic trisulfide and sulfur-selenium mixtures.  As a variant, the material constituting the outer layer 16 can be one of the simple elements, such as arsenic, sulfur, iodine, selenium, tellurium, thallium. 



   One embodiment will now be described with reference to FIGS.  1 to 8, the sensitive element 10 being constituted by a paper base 12, covered with a thin film of pure silver constituting the layer 14, the thickness of which is of the order of a few angstroms.  The metal layer 14 is in turn covered with a solid outer layer 16, the thickness of which is also of the order of a few angstroms and which is in the form of a vitreous mass.  The sensitive element 10 is first exposed to electromagnetic radiation, as shown in FIGS.  1 and 2, this with a mask 18 interposed in the trajectory of the incident electromagnetic radiation 20, this radiation being constituted by white light, such as a powerful incandescent lamp. 

  Parts of the mask 18 are, as shown at 22, substantially transparent to electromagnetic radiation, while other parts, as shown at 24, are substantially opaque. 



  As a result, the surface of the sensing element 10 is selectively and discontinuously irradiated in areas, such as 26, which correspond to the transparent portions 22 of the mask 18, while the other portion 30 of the surface of the element sensitive 10 is protected from electromagnetic radiation 20, such areas 30 of the sensitive element corresponding to areas 24 of mask 18 which are opaque to electromagnetic radiation.  It is evident that as a variant, an appropriate image can be projected onto the sensitive element by conventional optical projection means. 



   After exposure of the sensitive element 10 for a determined period of time, amounting to at most a few seconds, an interaction caused by the radiation takes place between the material of the outer layer 16 and the metal layer or layer. metal 14 to areas 26 which have been subjected to this irradiation, resulting in the formation of an inter-reaction product which thoroughly depletes all of the metal, silver in this example, of the metal layer 14. 

  The zones 30 shown in FIGS.  1 and 2, of the sensitive element which are not subjected to irradiation remain intact, as shown at 34 in FIG.  3, each of these zones 34 comprising a pattern formed by the remainder of the metal layer 14 with an adherent covering of the outer layer 16 which corresponds to the opaque zones 24 of the mask 18 of FIGS.  1 and 2, or which correspond to the dark areas of the image projected on the clip.  After removal of the inter-reaction product 32, the finished object is the object 11 shown in FIG.  4, which exclusively comprises the paper base 12 carrying a pattern adhering thereto and formed by the zones 34 formed by the remaining portions of the silver layer 14 and of the outer layer 16 of arsenic trisulfide.  

  For some applications, such an object can be used as such without further processing. 



   If it is desired to remove the remainder of the outer layer 16, this can be removed in several different ways such as sublimation by heating, chemical dissolution or mechanical removal although in most applications it is possible to remove it. '' simultaneously removing both the inter-reaction product 32 and the remaining parts of the outer layer 16, this in a single operation which may be mechanical, or constituted by a chemical or heat sublimation process, or as indicated further in detail for obtaining the objects 11 'of FIGS.  5 and 7. 



   When using a sensitive element consisting of a flexible or foldable base, such as paper for example, which is covered with a thin metallic layer, such as silver, in an atmosphere charged with vapor of the material constituting the outer layer, such as arsenic trisulfide vapor, the inter-reaction product or the inter-reaction products are automatically sublimated when formed and the finished object 11 'consists exclusively of the base 12 provided with the metallic pattern shown at 36 in FIGS.  5 and 7, this metal pattern being formed by the remaining parts of the metal layer 14 which correspond to the parts of the original sensitive element which have not been subjected to irradiation. 



   Such finished objects, as shown at 11 'in FIGS.  5 and 7, are identical to the finished objects which can be obtained from the object 11 of FIG.  4, this after removal of the outer layer 16, which, as explained above, can be carried out at the same time as the removal of the inter-reaction product 32 of FIG.  3.  For certain applications, for example when it is desired to obtain a reproduction with high contrast of the original image, it may be advisable to color, or darken the metallic image 36 of the object 11 'of FIGS.  5 and 7.  This can be done by treating the metallic image 36 with an appropriate dye, dye or darkening agent. 



  For example in applications where the metallic image 36 is a silver image, the contrast thereof relative to the bottom of the base 12 may be increased or the image may be made dark by being subjected to vapor. Hydrogen sulfide.  After sinking, the object obtained is, as shown schematically in FIG. 



   8, provided with a metallic silver image 36 which is suitably dark so as to offer a high contrast relative to the visible background formed by the paper base 12. 



   Fig.  6 schematically shows a device for automatically processing a sensitive element 10 in the form of a continuous ribbon, this to obtain a finished object, for example, the printing of a
 original image or a succession of original images. 



   The tape for the photosensitive element is obtained from a roll 40 on the periphery of which the tape is wound.  An intermittent advancement mechanism, such as, for example, that shown at 42, is provided to unwind and pass suitable lengths of sensitive elements from the roll.  An exposure station 44 is provided for lengths
 of the continuous strip of sensitive element 10 which are suitably irradiated during each of the periods of immobility of the mechanism 42, this by means of a projector 46 or the like, arranged to project on the surface of the element an appropriate image for a period of time. predetermined period and at a suitable intensity. 



  After exposure, the tape is folded at the stripping station 48, onto a roll 50 of small radius, continuously rotating, causing the remaining parts of the outer layer to break into small pieces which easily separate from each other. the lower metal layer.  Such remaining areas of the outer layer correspond to areas of the sensing element which have not been irradiated, the interaction product to areas which were irradiated during exposure also breaking into small fragments which collapse. easily separate from the paper base. 

  Folding the tape over roll 50 is all that is needed to remove both the remnants of the outer layer and the inter-reaction product, while the parts of the metal layer corresponding to areas that have not. been irradiated during exposure continue to adhere to the paper base.  The easy stripping of the sensitive tape is particularly marked if one uses a sensitive element consisting of a paper base covered with a thin layer of silver, itself covered with a vitreous layer of arsenic trisulfide. 

  The areas of the sensing element which have been exposed to the incident light and which remain vitreous in appearance, separate from the paper base in much the same way as the remaining areas of the arsenic trisulfide layer which do not. have not been subjected to incident electromagnetic radiation during exposure.  This is apparently due to the fact that the silver layer has a strong adhesion with the paper base, so that the unreacted parts of the metal layer strongly adhere to the paper base. during the count.  The parts which reacted, however, show a weak bond with the paper base due to the fact that the metal layer in these areas has been completely consumed. 

  The outer layer, made of arsenic trisulfide, is glassy in appearance and behaves such that when bending with a small radius, the arsenic trisulfide layer breaks and detaches from the metal layer.  In areas which have been subjected to irradiation, the formation of the inter-reaction product appears to be due to a phenomenon of migration of ions or atoms from the metal layer or the metal layer in the vitreous material constituting the outer layer.  As a result, the inter-reaction zones also break into small fragments during low radius folding, these small fragments bursting and separating from the paper base. 



   In applications where the outer layer is of a material other than arsenic trisulfide, arsenic pentasulfide, mixtures of sulfur and iodine, and lead-iodine, it may be necessary, to facilitate the separation of unreacted parts of the outer layer and the inter-reaction product of the remaining metal layer and the substrate or base respectively, to sweep or brush the surface of the element when bending or apply on the surface of the element a flexible sheet covered with a substance having a high adhesive power. 



   After stripping, the continuous tape which has been exposed and stripped and which shows a metallic image on the paper base is passed through a station 52 to determine the color, where the tape is contacted with a vapor 54 which in the example described where the metallic image is a silver image, is hydrogen sulfide vapor.  The continuous tape whose surface bears a dark image is then fed by means of rollers 56 to a cutting station 58 where, if necessary, it is cut to the desired lengths. 

 

   It is obvious that if it is not necessary to darken the image, station 52 can be omitted and it is also evident that the scanning station can also be omitted in applications where the sensitive element is simply a base of. paper or board carrying a thin layer of metal which is exposed to electromagnetic radiation in a reaction atmosphere, such as an atmosphere of arsenic trisulfide, arsenic pentasulfide or the like. 



  In such applications, exposure station 44 includes an envelope for containing the vapors of the reaction material.  As well as a suitable heater. 



   We will describe with reference to FIGS.  9-18 of the drawing a sensitive element 110 with several layers.  In fig.  9-10, each of these layers is itself composed of two adherent layers 112 and 114 of different materials. 



  The multi-layered sensitive element 110 may be disposed on a support or substrate 116 although such a support or substrate may be omitted in some applications. 



   In the example shown, there is shown a sensitive element 110 which comprises three pairs of layers each consisting of two layers 112 and 114 of different materials, capable of interacting when exposed to electromagnetic radiation causing the formation of an inter-reaction product having physical and chemical characteristics different from those of the original constituents. 



   As explained above, each of the pairs of layers comprises a metallic layer 114, a metallic layer by which is meant a layer containing at least one metal, either alone, or alloyed with another metal, or with others. metals, or which is combined or mixed with another element or other elements.  The metallic layer 114 can thus comprise the common metal such as silver, nickel, copper, colombium, lead, iron, aluminum, chromium, etc.  The material of the layer 112 may be any one of a group of ternary materials including arsenic, sulfur, iodine, or arsenic, sulfur and bismuth, for example. 

  The material constituting the layer 112 may alternatively be one of a group of binary materials such as a halide, for example an iodide, a sulfide, an arsenide, a selenide, or a metal telluride, trisulfide. of arsenic, arsenic pentasulfide and sulfur-selenium mixtures.  As a variant, the materials constituting the layer 112 may be constituted by one of the simple elements which are present: arsenic, sulfur, iodine, selenium.  tellium, thallium. 



   Each of the layers 112 or 114 is relatively thin and can have a thickness ranging from a few atoms to several angstroms.  You can use as many pairs of layers as you want, the only condition being that each pair of layers allows the electromagnetic radiation used for the exposure to pass through and which can be made up of simple intense white light, so that this incident radiation can reach the inner layers during exposure.  Since some absorption of radiation occurs at each of the layers, the depth of penetration of the radiation is substantially proportional to the intensity of the radiation. 



   Exposure to electromagnetic radiation of a multi-layered photosensitive element can be effected by projecting an appropriate image onto the surface of the element, this exposure being shown in Figs.  9 and 10 as being effected through a mask 118 having areas, such as shown at 120, which pass radiation, and other areas such as shown at 122, which do not pass radiation.  As a result, the electromagnetic radiation schematically represented by arrows 124 can selectively and discontinuously strike the sensing element at the appropriate areas 126 which correspond to the shape or contour of the projected image, while other areas 128 are protected and are not irradiated. 

  When the intensity of the irradiation energy is sufficient, the radiation penetrates deep as shown by the arrows 130 to the irradiated areas 126, whereby the materials of the layers 112 and 114 interact to form a product. interaction as shown at 132 in FIG.  11.  The formation of these inter-reaction products causes a decrease in the adhesion of the intermediate layers, which allows the mechanical removal of the parts of the element 10 which have been exposed.  Alternatively, the inter-reaction product 132 can be selectively removed by chemical means or by heat sublimation. 



   An exemplary multi-layer sensitive element 110 comprises several pairs of various layers each containing a metallic layer 114 of silver and a layer 112 of arsenic trisulfide or arsenic pentasulfide, each of which has a glassy composition. letting through ordinary light.  The silver layer 114 is thin enough to pass intense white light so that, for proper irradiation, the formation of the inter-reaction product 132 extends deep through the thickness of the element. 110.  As a result, as shown for the sensitive element 110, provided with a support or substrate 116, the formation of the interaction product 132 thus formed also allows electromagnetic radiation to pass easily. 

  Accordingly, the formation of inter-reaction products does not substantially prevent the formation of inter-reaction products at the lower level of the structure when irradiation is suitable. 



   After removal of the inter-reaction product 132, a finished article 111 is obtained as shown in FIGS. 



  12 and 13, this object having empty spaces 134 corresponding to the irradiated areas and parts such as 136 and 138 corresponding to the areas which have not been irradiated. 



   If it is desired to obtain a finished object having hollow the outline of an image initially projected onto the sensitive element, the parts of the finished object 111 of FIGS. 



  12 and 13 delimited within the perimeter of this contour, are removed by conventional mechanical means or by subsequent exposure to electromagnetic variation by an appropriate mask allowing the radiation to strike the appropriate areas, such as 136, in order to cause the formation of an inter-reaction product weakening the bond between the layers, this to facilitate the mechanical removal of these layers.  Alternatively, this inter-reaction product can be removed chemically or by sublimation by application of heat.  The object obtained 111 'is shown in FIGS.  14 and 15 and it comprises raised portions 138 which correspond to the unexposed areas and recessed portions 140 constituting a recessed representation of the original image. 

 

   If it is desired to obtain the opposite result, the parts 138 of the object 111 of FIGS.  12 and 13 are removed leaving thus, as shown in FIG.  16, an object 111 "showing a relief image 142 of the original image. 



   Due to the gradual absorption of the radiation transmitted deep through the multiple layers of the sensing element, a finished object can be obtained with a relief image having a contour whose depth substantially represents the intensity of the radiation. having hit the element.  This object can be obtained as shown schematically in FIG.  17. 



  An element comprising several pairs of layers, each consisting of two layers 112 and 114 of different materials capable of interacting with each other, as explained previously, is irradiated through a mask 144 having parts 122 that do not allow radiation to pass. 124, parts 120 which allow the radiation to pass completely, and also parts 146 which only partially allow the radiation to pass.  These parts 146 of the mask 144 are represented in an arbitrary manner, as having a progressive increase in transparency to radiation, from the extreme left edge to the extreme right edge, as represented in FIG.  17. 

  Thus, the interaction caused by the radiation extends deep into the element at variable levels, as shown at 148, these levels corresponding to the different boundaries between two consecutive layers where the radiation is sufficient to cause sufficient product. inter
 reaction to obtain, for example, a weakening of the bond between the layers which is sufficient to facilitate mechanical removal of the parts of the sensitive element which have not been activated. 



   The object obtained, shown in FIG.  18, has profile recesses, as shown at 150, which extend to a depth at the appropriate boundary between the different layers 112 and 114 reached by radiation with sufficient intensity to cause the appropriate formation of the inter-product. -reaction. 



   Figs.  19-33 represent embodiments of means making it possible to obtain electrical circuits
 printed matter, separate resistors having a determined value, capacitors having determined values, and integrated circuits comprising resistors and capacitors of predetermined value, connections between them and input and output terminals. 



   The sensitive element, shown at 210 in FIGS.  19 and 20, comprises a metallic layer 212 constituted by a thin layer or film of one metal or of several metals; this layer may have a thickness ranging from a few atoms to several angstroms and it is covered with a layer 214 of a material capable, when exposed to electromagnetic radiation, of interacting with the metal or metals of the layer metallic 212 to form therewith an inter-reaction product or products having a chemical composition and physical and electrical characteristics such as resistivity, for example, which are different
 rents of those of the constituents. 

  Layer 214 is equal
 very thin, and of the same order of thickness as the metal layer 212, and it is deposited on this der
 negate by any conventional means such as vapor deposition, cathodic spraying, etc. 



   Layer 212 is made of metal, a mixture or
 an alloy of at least two metals, or in a combination
 combination of a metal or metals with another element
 or other elements.  The metal or metals of layer 212 include any common metals such as
 silver, copper, colombium, iron, aluminum,
 chrome, nickel, etc.  The material constituting the layer
 214, may be, as previously indicated, any one
 shell of a group of ternary materials, comprising
 arsenic, sulfur and iodine, or arsenic, sulfur and bismuth, for example. 

  As a variant, the material constituting the layer 214 can be any one of the binary materials such as a halide, for example an iodide, a sulfide, an arsenide, a selenide, or a metal telluride, arsenic trisulfide, arsenic pentasulfide, and mixtures of sulfur and selenium.  The material of the layer 214 can also be made from any single element, such as arsenic, sulfur, iodine, selenium, tellurium and thallium. 



   Three exemplary embodiments of the present invention are explained in detail, preferably in connection with a radiation sensitive element such as that shown at 210 and which comprises a metallic layer 212 consisting of a silver strip or foil, at '. follow, in chromium, in nickel or a mixture thereof, which is provided with a solid, adhesive layer, 214 of arsenic trisulphide or of arsenic pentasulphide, this although practically the same results are obtained using any of the components listed above.  In certain applications, there are certain advantages in using, as the material constituting the layer 214, a liquid phase, or preferably a vapor phase. 

  By using the material constituting the layer 214 in the vapor state, one obtains the clear advantage that the finished article, the electrical component or the electrical circuit, does not need to be protected by means of a screen against a new exposure to electromagnetic radiation.  The same result can however be obtained by removing the interaction products and the unexposed parts of the layer 214, after exposure under control of the sensitive element to electromagnetic radiation, in order to avoid deterioration or change. electrical characteristics of components or circuits that would result from subsequent exposure to electromagnetic radiation. 



  For certain applications, however, the use of a sensitive element comprising a layer 214 in solid form has the advantage of good electrical insulation, when a material such as arsenic trisulfide, having a resistivity of about 10 -105 ohm / cm is used as part of an electrical component or a circuit, this as will be described later.  Accordingly, a sensitive element was chosen comprising a layer 214 made of a material in a solid phase. 



   The sensitive element 210 is provided (see fig.  19 and 20) of two terminals 216 and 218 electrically connected through a part or a segment of a metallic layer 212.  The sensitive element 210 is exposed to incident electromagnetic radiation, such as ordinary white light 222, emitted by a light source consisting for example of electric bulbs 220.  The light 222 strikes the surface of the sensitive element 210 after having passed through a mask 224, which, in the example chosen, comprises parts 226 which are substantially transparent to light, and a part 230 which is not. only partially transparent to light.  

  As a result, the surface of the sensing element 210 is completely irradiated in areas such as those shown at 232 and which correspond to parts 226 of mask 224 which fully pass light 222, while other parts, such as those shown at 234, are substantially completely protected from the effect of light.  Another part, such as that shown at 236, is irradiated with light of reduced intensity.  For a given exposure, parts of the metal layer 212 corresponding to the completely irradiated parts 232 are entirely consumed under the effect of the interaction between the metal layer and the material, such as arsenic trisulfide, layer 214, this inter-reaction being caused by light. 

  The parts of the metal layer 212 corresponding to the exposed parts 234 are not affected, while the part of the metal layer corresponding to the partially irradiated zone 236 is partially etched in depth by an amount corresponding to this irradiation intensity.  Accordingly, a section taken through the sensing element 210 through the axis including terminal 216 and terminal 218 is as shown schematically in FIG.  21, the metal layer 212 comprising parts 238 which have the original thickness and which are electrically connected to the terminals 216 and 218 by a part 240 whose thickness is reduced,
The thickness of the part 240 being substantially inversely proportional to the exposure to incident light of the zone 236 shown in FIG.  19 of the sensitive element 210. 

  The object obtained is constituted by a resistance having a determined value which depends on the resistivity of the metal or metals constituting the layer 212, on the cross section offered to the current passing through it, and on the length of the path traveled by the flow.  Accordingly, the total value of the resistor thus formed and which consists of the remaining portion of the metal layer 212 which is located between the terminals 216 and 218, can be determined according to the geometric dimension of the image projected onto the sensitive element and according to the duration of the exposure of the zone 236 of the element. 



     When the predetermined value of the resistance Rx is obtained, the irradiation of the sensitive element 210 is stopped and the element can be housed in a screen in order to protect it permanently against further irradiation, or it can be covered. a layer of lacquer or a layer of paint opaque to electromagnetic radiations which can modify the element and change its value.  As a variant, the remainder of the layer 214, shown at 242 in FIG.  21, which has not been subjected to the radiation, and the parts of the layer 214, shown at 244, which comprise the inter-reaction product caused by the inter-reaction between this layer and the metal layer 212.  This removal can be done mechanically or chemically. 



   The resistance value obtained by the arrangement according to fig.  19 can be continuously monitored, using, for example, an ohmmeter connected to terminals 216 and 218, or using a bridge, such as that shown and which comprises the series of resistors R1, R2, Rx and resistor R5 which are arranged in a bridge comprising an electric current source 245 placed in one diagonal of the bridge and a measuring instrument 46 placed in the other diagonal of the bridge. 

  When the bridge is in equilibrium, the current flowing through the measuring instrument 246 is zero and the value of the resistance Rx is given by the formula:
EMI8. 1

 Accordingly, for given values of R1, R, and R, one can constantly monitor the value of Rx until it reaches a determined amount, which is indicated by the fact that bridge 246 is in equilibrium. . 



  As shown schematically, the measuring instrument 246 can be arranged to close a switch 248 when the instrument indicates 0, or the instrument 246 can be replaced by a relay such as that shown at 250 and which is arranged to open the switch. - switch 248 when a predetermined value of Rx is obtained, this so as to disconnect the lamps 220 from the power source 252 and interrupt the exposure of element 210 to light. 



   The resistivity of the part 214 exposed to the radiation is decreased as a function of the exposure to the latter, this being the formation of the inter-reaction product which tends to remain as a solid solution inside. of layer 214.  As mentioned above, the resistivity of arsenic trisulfide is 10-15 ohm / cm and the resistivity of a layer 214 of arsenic trisulfide can be reduced by a considerable amount if it is deposited in contact with a layer. of metal 212, this part made for example of silver, the resistivity of the arsenic trisulfide layer decreasing in proportion to the exposure and tending towards a minimum value which remains constant after all the silver in the metallic layer has been exhausted . 

  Accordingly, resistance can be made using a sensing element 210, as shown in fig.  22, which is identical to the sensitive element 210 of FIG.  20, but which is provided with a terminal 216 connected to the layer 214, and another terminal 218 connected to the metallic layer 212.  The exposure of the sensitive element 210 of FIG.  22, to electromagnetic radiation through a mask such as mask 247 of FIG.  23, which has along a longitudinal section thereof an end part 249 completely transparent to electromagnetic radiation, another end part 251 substantially not allowing electromagnetic radiation to pass, as well as an intermediate part 253 whose transparency gradually decreasing from part 249 to part 251 leads to obtaining an object which, as shown in fig. 

   23, presents a metallic layer 212 connected to the terminal 218 which, seen in section, comprises a part 254 going gradually decreasing, and which corresponds to the part 253 of the mask 247, the transparency of which varies gradually.  The finished object also comprises a part, which as shown at 256, is provided with the area of the layer 214 which has not reacted and with a neighboring part and fixed to the terminal 216 which is constituted by an area of the layers. 212 and 214 which reacted completely and this as shown in 258. 

  The part of the layer 214 which corresponds to the part 253, the transparency of which gradually decreases of the mask 247 has a gradually decreasing resistivity, from the right to the left, when one looks at FIG.  23, so that the total resistance between terminals 216 and 218 can be determined, within certain limits, depending on the total exposure of the element to electromagnetic radiation. 

 

   It can thus be seen that electrical components such as resistors, of determined value, can be obtained by using the sensitive elements described and by applying the method described to them. 



   Figs.  24 and 25 show a sensitive element 210 ′ corresponding to another embodiment, which, as can be clearly seen in the sectional view of FIG.  25, comprises a metal layer 212 covered with a layer 214 of a material capable, when exposed to electromagnetic radiation, to interact with the metal or metals of the metal layer 212.  The metallic layer 212 is in turn disposed on one face of a dielectric layer 260, to which it adheres, this dielectric layer being provided with another metallic layer 262 on its other face.  A new electrical terminal 266 is attached to the metal layer 262. 

  Such an assembly constitutes a capacitor comprising parallel plates defined by metal layers 212 and 263 and whose capacitance, as is well known, is given by the following formula:
 KA micromicrofarad
 c = KA / d micromicrofarad
 d in which
A = effective surface of the plates in cm d = thickness of the dielectric in cm
K = 0.0085 Er, where Er is equal to the dielectric constant
 relative to air. 



   As it is well known, the effective area A of a capacitor with parallel plates, the capacitance of which is given by the above formula, is constituted by the coincident surfaces of the plates and to decrease the capacitance of a capacitor it is sufficient to decrease the coincident surfaces of the plates, which can be done by decreasing the area of one of the plates and not modifying the surface of the other plate.  This is done, according to one embodiment of the invention, by providing a screen 268 capable of masking the sensitive surface of the element 210 'against electromagnetic radiation such as light, which is shown at 222, and which is emitted by a source such as incandescent lamps 220. 



   The capacitor formed by element 210 'is connected in a bridge such as that shown in FIG.  24, this bridge comprising an impedance Zx and known impedances Zt, Z2 and Za.     An alternating current source 270 is connected in a diagonal of the bridge, this source having a known frequency f. 



   A measuring instrument 246 is plugged in across the diagonal of the bridge.  When equilibrium is reached, instrument 246 marks 0 and the impedance Zx is given by the formula:
EMI9. 1
 and the capacitance of the capacitor is given by the formula:
EMI9. 2

 Instrument 246 may be arranged to open a switch 248 disposed in series between an electrical power source 252 and lamps 220 or, alternatively, a relay 250 may be used to directly open switch 248 when the impedance Zx of the capacitor reaches a determined value. 



   To decrease the capacitance of the capacitor, screen 268 is moved in the direction of arrow 272, see fig.  24 and 25, so as to increase the surface of the metal layer 212 which interacts with the outer layer 214 under the influence of electromagnetic radiation striking them. 



   The capacitor comprises, as shown in FIG.  26, after exposure of the element 210 'to electromagnetic radiation, a first plate formed by the metal layer 262 connected to the terminal 266, and a second plate formed by the remaining unreacted area of the metal layer 212 which is connected to terminal 264 and which is separated by a dielectric layer 260.  The parts or areas of the metal layer 212 which have not been protected by the screen 268 against electromagnetic radiation interact with the material of the layer 214, which deeply consumes the metal of the layer 212 and causes the formation of inter-reaction products as shown at 274, which allows the effective area of the capacitor to be adjusted. 



   Thus it is possible, by applying the principles of the invention, to establish a capacitor of predetermined value and which is precisely adjusted to a predetermined capacitance value, with the aid of electromagnetic radiation such as light. 



   Figs.  27 and 28 show a variant of a capacitor which, as best seen in FIG.  28, comprises a sensitive element 210 "comprising itself a layer 214 established with the same material as the layers 214 of the sensitive elements described above, and which, for example, may be arsenic trisulfide.  This layer carries on each of its faces a thin metal layer 212, thin enough to allow electromagnetic radiation to which they are exposed to pass, so as to cause an inter-reaction between the material of the layer 214 and the layers of metal or of metals 212. 

  A screen is arranged as shown at 276, this screen being slidable such that part of the sensing element 210 "can be subjected to radiation on at least one side or, as shown, on both sides, so forming in the areas which have been irradiated an inter-reaction product 274 (see fig.  29) consuming the areas of the metal layers 212 which have been struck by the radiation.  The object obtained is, as shown in FIG.  29, a capacitor having a determined value which depends on the extent of the zones subjected to electromagnetic radiation, the plates of this capacitor being determined by the parts of the layers 212 which have not been subjected to the reaction and which are connected to the terminals 264 and 266. 



   Sensitive elements can, as explained above, be used to obtain integrated circuits this by simple exposure to electromagnetic radiation through a mask, or by projection onto them of a determined pattern, an example of which is shown in Figs. .  30 to 33.  A sensitive element 280 is obtained by covering a dielectric sheet 260 of the desired thickness with a thin metallic layer 212 on both sides of the sheet, this metallic layer being in turn covered with an outer layer 214 of a material capable of react with the metal of the layer 212 when it is subjected to electromagnetic radiation, this as explained above.  The first face 282 of the sensitive element 280 is exposed to radiation, through a mask, or by irradiating a certain pattern, as shown in FIG.  30. 

  This pattern comprises parts shown in black such as 286 which protect the face 282 from incident radiation, other parts such as 288 allowing all of the light to strike this face and other parts such as 290 allowing a reduced irradiation of the sensitive surface.  The other face 284 of element 280 is also exposed to electromagnetic radiation as shown in FIG.  31.  Some parts like 288 are subjected to all of the radiation, other parts as shown at 290 are subjected to reduced radiation and other parts as shown at 286 are protected from the action of electromagnetic radiation. 

  Terminals 292, 294 and 296 are attached, either before or after exposure to electromagnetic radiation, to the edge of metal layer 212 disposed on face 282, and terminals 298 and 300 are attached to metal layer 212 disposed on face 284.  The object is constituted by an integrated circuit in which parts of the layers 212 which have not been subjected to the reaction and which correspond to the zones 286, constitute conductors or capacitor plates and in which all the zones such as 290 , which have been partially exposed to radiation constitute a resistance, the value of which depends on the intensity of the radiation and the geometric dimensions of the area.  The object obtained is an electrical circuit, the equivalent diagram of which is shown in fig.  32. 

  This circuit comprises a plate 302 of a capacitor 304, which is connected to a terminal 294 by a resistor 306, to a terminal 292 by a resistor 308 and to a terminal 296 by a conductor 310, these elements being arranged on the face 282 of element 280. 



  The other plate 312 of the capacitor 304 is connected to a terminal 298 by a resistor 314 and is also connected to a terminal 300 by a resistor 316, the different zones shown in FIGS.  30 and 31 being identified by the same reference indices as in the diagram of FIG.  32 in order to facilitate the understanding of the equivalence between these figures. 

  If the surface of one of the plates 302 or 312 of the capacitor 304 needs to be adjusted in order to obtain a more precise value for the capacitance of the capacitor, or to fine tune the circuit with respect to the characteristic electrical system, a zone plates, such as that shown at 318 for the plate 302 in FIG.  30, can then be individually exposed to electromagnetic radiation as explained above and the value of each of the resistors can also be precisely determined by subsequent discontinuous and selective exposures to electromagnetic radiation. 

  However, it should be borne in mind that the controllable variations of the values of the components can only be done in the direction of a decrease in the capacitance with regard to the capacitors and in the direction of an increase of the resistance value with regard to the resistors. 



   The completed monolithic circuit may be mounted in an enclosure arranged to protect the element against subsequent irradiation, or it may be covered with an opaque varnish or the like or else unreacted and reacted parts of layers 214 may be coated. be removed mechanically or chemically so as to form a circuit as shown in FIG. 



  33, which is entirely equivalent to the diagram of FIG.  32. 



   Given that the sensitive elements described behave under certain conditions and for certain groups of materials, such as semiconductors, it is also possible to obtain complete integrated circuits comprising unidirectional elements and unidirectional elements provided with control means, such as diodes and transistors and the like. 



   We will now describe with reference to FIGS.  34 to 55, the methods of establishing metallic patterns obtained by projecting an image of the pattern to be reproduced onto a radiation sensitive element and essentially comprising a metallic layer covered with an adherent layer of a capable material, when exposed to electromagnetic radiation, to react with the metal of the metal layer.  After exposure, those parts of the outer layer whose adhesion to the metal in the layer has been reduced due to exposure are removed.  Thus, there is selective and discontinuous exposure of the surface areas of the metal layer which are then electrically plated or electrochemically eroded, depending on whether the pattern is to be in relief or in hollow. 



   Alternatively, sensitive elements comprising a metallic layer thin enough to pass radiation can be imaged to the pattern on the metallic layer, thereby having the effect of deeply consuming selected and discontinuous portions of the metallic layer.  The remaining parts of the metal layer which have not been subjected to the reaction are then electrically plated. 



   As shown in fig.  34, the first step is to expose a sensitive element 410 to an incident electromagnetic reaction 412, such as light.  The sensitive element 410 is exposed, for example through a mask 414 having a determined pattern consisting of parts which, as shown at 416 easily pass incident radiation, and other parts, as shown at 418, which do not allow electromagnetic radiation to pass. 



   The sensitive element 410 consists essentially of a metal plate 420 provided with an outer layer 422 of a material capable of interacting with the metal or metals of the metal layer 420 following exposure to electromagnetic radiation. such as light.  The metallic layer 420 consists of a sheet or a film containing at least one metal, either alone or alloyed with another metal or with other metals, or even combined or mixed with an element or other elements.  The metallic layer 420 can thus comprise any of the common metals such as silver, copper, colombium, lead, iron,
Aluminum, chromium, nickel, etc.  The outer layer 422 which is deposited on the metal layer while adhering to the latter, comprises one of the materials described above.  

  The metallic layer 420 may be provided, if necessary for certain applications, with a metallic or non-metallic support or substratum as represented by the dotted line 424.  Each of the layers may have a thickness of the order of a few atoms or angstroms or of the order of a few hundredths of a millimeter (a few mills). 



   The sensitive element 410 consisting for example of a metallic silver layer 420 covered with an outer layer 422 of arsenic trisulfide, is exposed to incident electromagnetic radiation through a mask 414 as described above, or is exposed to a appropriate motive which is projected onto it only by appropriate means.  During the exposure of the sensitive element, which as shown is effected on the face provided with the outer layer 422, certain areas, such as those shown at 426, are struck by the incident electromagnetic radiation 412, while other areas, such as those shown at 428, are not subjected to irradiation. 

  This selective and discontinuous exposure to electromagnetic radiation results in a selective and discontinuous formation of one or more interaction products, these in discontinuous areas of the layer forming the boundary between the metallic layer of silver. 420 and the outer arsenic trisulfide layer 422, as shown at 430 in FIG.  35.  The areas which are not subjected to irradiation are not disturbed, as shown at 432.  The formation of this inter-reaction product 430, at the irradiated areas, has the effect of causing a selective and discontinuous reduction in the adhesion force between the outer layer 422 of arsenic trisulfide and the metallic layer of silver 420. 

  The portions of the arsenic trisulfide outer layer 422 which correspond to the irradiated areas can be removed by means such as, for example, the non-rigid sheet shown at 434 in FIG.  36 and which is provided on one face 436 with an adhesive product bonding with the outer layer 422, this with a force intermediate between the adhesion force of the layer 422 with the metallic layer 420 and the reduced adhesion force obtained to areas that have been irradiated. 

  Thus, when the covered sheet 434 is removed, the portions of the outer layer 422 corresponding to the irradiated areas of the sensing element 410 are pulled out and removed by the sheet 434 as shown at 438, due to the fact that the adhesion of the foil is stronger than the adhesion between the two layers at the irradiated areas, while the other parts, such as those shown at 440, of the outer layer 422, continue to adhere firmly to the metal layer 420 and separate cleanly from the parts 438 while remaining in place, so that the stripped sensitive element is presented as shown schematically in FIG.  37 with discontinuous surface areas 442 of the metal layer which are exposed or uncovered and no longer protected by the outer layer 422 of arsenic trisulfide. 



   The areas 442 of the metal layer 420 which have been discovered are then plated by being placed in a reservoir 444 (see fig.  38) which contains a suitable electrolyte 446 in which the element 410 is immersed, the metallic layer 420 being placed in a direct current circuit 448 thus forming a cathode.  A suitable metal plate or block as shown at 450 is connected to the negative terminal of source 448.  Depending on the electrolyte used and the composition of the anode plate 450, a metal or metals of determined composition are deposited on the metal layer 420 in areas 442 which are not protected by the remaining parts of the outer layer 422. 

  It is clear that if the metallic layer 420 is not provided with an insulating support or substratum 424, it is preferable to cover the surface of the metallic layer 420 which is opposite to the surface carrying the remaining parts 440 of the outer layer. 422 with an insulating paint or varnish, this so as to prevent this face from being plated if such a plating is not desired. 



  The material forming the outer layer 422 being in all practical cases constituted by a dielectric, as is the case with arsenic trisulfide or arsenic pentasulfide, no plating occurs on the surface of the remaining parts of the layer. 422 in contact with the electrolyte.  When somewhat better current conducting materials, such as arsenic, bismuth or the like, are used to form the outer layer 422, the plating of the outer layer which may result is of little importance. given the low adhesion of this veneer to the base material, and the thinness of the covering which can then be easily removed by simple mechanical or chemical cleaning. 

  Alternatively, when the outer layer 422 is of a material which can undergo plating, a simple operation of covering the outer surface of the remaining portions of the outer layer with a non-conductive material or an oily material is sufficient to remove any tendency of this outer surface to flatten during the plating operation.  It is easy to obtain information relating to the baths and the plating processes which can be used in different books, such as for example the book: Modern Electroplating by A. G.  Gray, posted by John
Wiley and Sons, Inc. , New York, in 1953 - or Electroplating Engineering Handbook by A. K. 

  Graham, published by Reinhold Publishing Corporation, New York in 1955, and Printed and Integrated Circuitry by T. D. 



  Sehlabach and D. K.  Rider, posted by McGraw-Hill
Book Company, Inc.  New York, in 1963. 



   The object obtained after plating is shown as shown schematically in section at A in FIG.  39 or at A 'in fig.  40.  The plated portions 452 form a metallic relief pattern corresponding to the pattern of electromagnetic radiation to which the sensitive element is exposed.  The plating operation is carried out for a period which is sufficient to apply a metallic coating 452 of the desired thickness and which is deposited on the exposed or uncovered areas of the metallic layer 420. 

  The thickness of the veneer is shown in fig.  39 as being less than the thickness of the remaining portions 440 of the outer layer 422.    It is clear that when one wants to obtain a thicker veneer, it suffices to continue the operation according to the arrangement of FIG.  38, until the veneer is thicker, this as shown at 452 in FIG.  40, where the veneer is thicker than the remaining portions 440 of the outer layer 422. 



   For certain applications, the object obtained can be used as represented at A and A 'in FIGS.  39 and 40 respectively, but for other operations it may be appropriate to remove the remaining parts of the outer layer 422. 



   The remaining parts 440 of the layer 422 can then be removed by any suitable means such as chemical dissolution in a suitable solvent or sublimation by application of heat or else by a second exposure to electromagnetic radiation 412, this as shown in FIG. .  41.  This second exposure causes an inter-reaction between the material of the outer layer 422, arsenic trisulfide, for example.  in the remaining parts 440 thereof, and the metal, silver for example, of the metal layer 420, this in the areas where this metal and this material are juxtaposed, this having the effect of forming a product inter-reaction as shown in 454.  

  Such exposure to electromagnetic radiation, a second time, considerably weakened the bond between the parts 440 of the layer 422 and the metal layer 420, so that the parts 440 of the outer layer can be easily removed by peeling or peeling. 'using, for example, the means described and shown in FIG.  36.  The object obtained then appears more or less like the object B of FIG.  42 which essentially consists of a metallic layer 420 carrying thereon a plated metallic pattern 452. 

  If the second exposure to electromagnetic radiation is carried out for a period and with an intensity which is sufficient to thoroughly consume the consistent parts of the metallic layer 420, still covered with the outer layer, the finished product, obtained after removal of the product d 'inter-reaction formed during the second exposure, is presented substantially as shown at C in FIG.  43.  The object C has voids 456 formed in the metal layer 420 as a result of the second exposure to electromagnetic radiation, so that the finished object has a metal pattern with high relief and including the metal plated parts 452 which are superimposed on the remaining parts of the metal layer 420. 



   According to another embodiment, the sensitive element 410 of FIG.  37 can, after having been exposed and stripped, be subjected to an electrochemical erosion treatment, this according to the arrangement shown schematically in FIG.  44.  Element 410, which primarily consists of a metal layer 420 discontinuously provided with remaining portions 440 of outer layer 422, is placed in an enclosure 460 including a bottom 462 and side walls 464. 

  The enclosure 460 is made of a non-conductive material and comprises means such as the contact 466 for electrically connecting the metallic layer 420 of the element 410 to the positive terminal of a direct current source 468, in order to make this layer metallic 420 anode relative to a conductive plate 470 which is made cathodic by being connected by means of the contact 471 to the negative terminal of the direct current source 468.  The enclosure 460 has an inlet 472 and an outlet 474 for an electrolytic solution 476 which circulates at high speed and at high pressure in the space defined between the element 410 and the cathode plate 468. 

  Thanks to the arrangement according to fig.  44 and the well-known principle of electrochemical machining, the exposed areas 442 of the element 410 are electrochemically eroded, while the areas protected by the retained portions of the outer layer 422 which acts as an insulator are not affected, when the A current is passed at a potential of 10 to 20 volts, for example, and at high density through the electrolyte.  A suitable electrolyte happens to be an aqueous solution of sodium chloride which is applied in the gap between plate 470 and element 410 at a pressure between 1 kilogram per cm2 and 5 kilograms per cm2 (10 to 50p. s. i. ). 



   If the electrochemical operation carried out in the arrangement shown in FIG.  44 is of short duration only, the object obtained is the object B shown in FIG. 



  45 and it consists of the remaining parts 440 of the outer layer 422 which adheres to the metal layer 420 and the metal layer 420 whose exposed parts have been eroded to a depth 478 which depends on the duration of the erosion operation. electrochemical for a determined current density. 



   After removal of the remaining parts 440 of the outer layer 422, for example by means of a second exposure to electromagnetic radiation, which, as explained below decreases the adhesive forces between the metal layer and the outer layers by facilitating thus the removal of the remaining parts of said outer layer, finished object is as shown at E in fig.  46.  It mainly consists of a metallic layer 422 comprising on its surface a raised metallic pattern as shown at 480 and which is formed by the areas of the metallic layer which were protected by the remaining parts of the outer layer 422 during the operation. electrochemical erosion, these areas emerging from less protected and eroded areas. 



   If the continuation of the electro-chemical operation according to the arrangement shown in fig.  44 continues until the parts of the metal layer 412 not protected by the remaining parts 440 of the outer layer 422 until erosion is effected throughout the thickness of the metal layer, the object obtained is such as that shown at F in FIG.  47.  Object F consists mainly of the remaining parts 482 of the metallic layer 422 covered by the remaining parts 440 of the outer layer 422. 

  After removing the remaining parts of the outer layer 422, for example by exposure to electromagnetic radiation followed by tearing off according to the process described above, the object obtained looks like that shown at G in FIG.  48 and it mainly comprises a metallic pattern formed by the remaining parts 482 of the metallic layer 420. 



   Fig.  49 shows a sensitive element 410 ′ comprising a thin metal layer 420 made of a metal such as one of those mentioned above, and it can for example be constituted by a thin film of metal, thin enough to allow electromagnetic radiation such as light, this film being placed on a substrate 422 made of any of the materials mentioned above and which are capable, when exposed to electromagnetic radiation, to interact with the metal of the metal layer 420 .  The substrate 422 may, for example, be in the form of a glassy layer of arsenic trisulfide or arsenic pentasulfide. 

  For certain applications, the substrate 422 can be provided with a metallic or non-metallic support, not shown, on its surface opposite to that bearing the metallic layer 420. 



   The sensitive element 410 'is shown in FIG.  49 while it is exposed to the incident electromagnetic radiation 412 on its side bearing the metallic layer. 



  The exposure is effected through a mask 414 comprising discontinuous portions 416 easily allowing this radiation to pass, so that the surface of the metallic layer 420 is selectively and discontinuously irradiated by the radiation incident to the portions 426, while other parts 428 are not disturbed. 

 

  At the boundary between the metallic layer 420 and the substrate 422 and in the zones which have been thus exposed for a sufficiently long time or with a sufficient intensity, or else both, one or more products of interaction are formed as shown at 430 on the left. fig.  50.  Given the thinness of the metal layer 420, these products deeply consume all the metal in the metal layer.  The other parts 432 of the boundary layer which are protected from electromagnetic radiation retain the parts 484 of the metallic layer 420 which have not undergone any reaction.  After the inter-reaction product 430 has been removed, mechanically by stripping or chemically by dissolving the inter-reaction product in an aqueous solution of sodium sulfide or sodium hydroxide, the sensitive element is presented as shown in fig.  51. 

  It comprises a substrate 422 provided with discontinuous portions 484 of the metallic layer 420 which forms a pattern corresponding to the pattern formed by the mask through which the sensitive element was originally exposed to radiation or, alternatively, to the projected pattern. on the surface of the metal layer 420.  The discontinuous zones 486 of the parts 484 of the metal layer 420 can then be electrically plated with a suitable metal, this using run of the devices described above with reference to FIG.  38, the metal layer 420 being connected to the positive terminal of the power source.  After plating, the object obtained appears as shown at H in fig.  52. 

  The object H comprises the remaining parts 484 of the metallic layer 420 which adhere to the substrate 422 and whose surfaces 486 are plated as shown at 488 with an additional metal.  Such an object can for example constitute an electric circuit. 



   If, however, it is desired to obtain a finished article from which the substrate 422 is removed, the latter can be dissolved in a suitable solvent or, alternatively, the substrate 422 can be removed by subjecting the element to a second exposure, as shown in FIG. .  53, and irradiating the substrate with electromagnetic radiation 412 so as to cause the formation of an interaction product 454 at the boundary surface between the remaining portions 484 of the metal layer 420 and the substrate adjacent 422. 

  Such a second exposure requires, as mentioned above, a duration and an intensity just necessary to reduce the adhesive force between the remaining parts 484 of the metal layer 420 and the contact area of the substrate 422.  so that this substrate 422 can then be easily torn from the metal layer 420, thus giving the finished object shown at J in FIG. 54. 



   If the intensity and duration of the second exposure are sufficient to consume all the remaining parts 484 of the metal layer 420, the object obtained is as shown at K in FIG.  55.  The object K consists exclusively of a metallic pattern formed by the plated parts 488 of the plated metal.  In this variant, the sensitive element was only used as a support to obtain an appropriate metallic pattern corresponding to the pattern originally projected on the element, which was made up of metals or alloys of suitable composition and thickness.  Such a process is particularly useful when it is desired to obtain a metallic pattern of metal which is incapable of reacting with the material forming the layer 422 under the effect of electromagnetic radiation. 



   It has thus been shown that the various embodiments of the process make it possible to establish metal patterns in relief using a sensitive element which is then treated electrochemically to plate selected and discontinuous parts of the element or , alternatively, to erode selected and discontinuous parts of the element. 



   Figs.  56 to 65 show another embodiment of the method for establishing a metallic relief pattern by irradiating, in accordance with the pattern to be reproduced, an element sensitive to radiation and to heat and which mainly comprises a layer of metal covered with an adhesive layer on the outside in a material capable of interacting with the metal either when it is exposed to electromagnetic radiation or when it is subjected to heat. 

  After exposure to radiation which causes a reduction in the adhesion between the outer layer and the metal layer, the element is stripped of the parts of the outer layer corresponding to the irradiated areas, then is then heated to cause an inter-reaction between. the remaining parts of the outer layer and the metal layer, which has the effect of consuming in depth and thus etching the metal of the metal layer. 



   Fig.  56 shows schematically and in section an element 510 sensitive to electromagnetic radiation and which consists mainly, as explained above, of a metal layer 512 provided with an outer adhesive layer 514 of a material capable of interacting with the metal of the metal layer 512, when exposed to electromagnetic radiation such as light.  It has been found that the process can be made more efficient by using certain metals for the metal layer 512 and certain materials for the outer layer 514 which exhibit better affinity for each other upon exposure. electromagnetic radiation or especially under the effect of heat. 

  Preferably, the metal constituting the metallic layer 512 consists of silver or copper and the material constituting the outer layer 514 belongs to the group comprising arsenic trisulfide, arsenic pentasulfide, lead-iodine mixtures and arsenic-sulfur-halide mixtures, such as, for example, arsenic-sulfur-iodine.  However, any other metal mentioned above in the present description can be used to constitute the metal layer 512, this either alone, or alloyed with other metals, or combined with one or other elements, these metals being nickel, colombium, lead, iron, chromium, aluminum, etc. 



   The outer layer 514 can also be any of the following other materials: arsenic, sulfur, halogens, selenium, tellurium, thallium, or a metal halide, sulfide, arsenide, selenide or telluride and mixtures of sulfur-selenium, or alternatively in a ternary material containing arsenic, sulfur and bismuth in place of the material mentioned above. 



   The material forming the outer layer 514 is deposited on the metallic layer in glassy form, preferably by vacuum deposition or the like.  The adhesive force between the metal layer 512 and the outer layer 514 at the boundary surface 516 between them is very large.  The thickness of each of the metal layers 512 and of the outer layers 514 is preferably on the order of a few atoms to a few microns. 

 

   During the implementation of the method, the sensitive element 510 is first exposed, as explained above, to an incident electromagnetic radiation, such as light, this as represented by the arrows 518.  This radiation strikes the sensitive element, forming a determined pattern.  Such selective and discontinuous exposure of the sensing element can be effected, for example, by exposing the sensing element 510 to such incident light through a mask 520 comprising portions 522 easily passing light and other portions 524. not letting through the light. 

  It is clear that means other than the mask 520 can be used to expose the element 510 to the incident light in order to allow this light to strike the element in a selective and discontinuous manner, these means possibly being constituted by well known image projection systems. 



   Under the influence of such a selective and discrete irradiation of the sensitive element 510, an inter-reaction occurs at the boundary 516 between the metal layer 513 and the outer layer 514 which causes the formation of an inter-product. -reaction as shown at 526 in FIG.  57, this in the zones 527 of this boundary surface which correspond to the zones which were subjected to lighting during the exposure, while the other zones of the boundary surface, such as represented at 528, which were protected from the illumination by the non-transparent parts 524 of the mask 520 are not disturbed. 



   Boundary areas 527 form, as a result of the formation of the inter-reaction product 526, parts where the adhesion between the outer layer 514 and the metal layer 512 is reduced, which allows the layer 514 to be. selectively and discontinuously torn from the metal layer, in the areas which have been irradiated.  The tearing can be carried out by any suitable mechanical means such as bending the element or by a heat treatment of the element, each of these treatments causing the separation of the parts of the layer 514 corresponding to the zones 527, of the layer. metalic 512.  However, the tearing is preferably carried out using a flexible sheet 530, FIG.  58, which is provided on one face 532 thereof with an adhesive cover bonding strongly with the outer surface of the outer layer 514. 

  The adhesive force between the flexible sheet 530 and the outer surface of the outer layer 514, however, is less than the normal adhesive force between the outer layer 514 and the metal layer 512 at the areas 528 which have not been subjected to the irradiation.  Accordingly, when the flexible sheet 530 is pulled back as shown in FIG.  58, it removes discontinuous parts 534 of the outer layer 514 which correspond to the irradiated zones 527 of the sensitive element and which easily separate from the parts 536 of the outer layer, corresponding to the non-irradiated zones 528 of the boundary surface 516. 



   The sensitive element after having been exposed and stripped is then subjected to the action of heat, as shown in fig.  59, this by being heated rapidly to a temperature which is high enough to cause a thermal reaction between the material of the remaining portions 536 of the outer layer 514 and the metal of the metal layer 512 at the contact surface between these two.  This temperature is usually on the order of a few hundred degrees and the thermal reaction is carried out simply by placing the exposed and stripped element on a hot plate similar to a hot plate of an electric stove, the metal layer 512 being in contact. with the hot surface. 

  Under the influence of the heat supplied to the element, the remaining parts 536 of the outer layer 514 react rapidly with the metal of the metal layer 512 at the areas 528 of contact between them, this causing a deep etching of the metal layer. to these contact areas.  The product (s) formed by the inter-reaction between the remaining portions of the outer layer 514 with the metal of the metal layer 512, which inter-reaction is caused by heat, are vaporized or sublimated as they are formed. , so that the obtained object A1 is constituted by a metal layer 512 provided with a relief pattern formed by recessed parts, as represented at 538 in FIG.  60. 

  These recessed parts correspond to the surface of the metal layer 512 which was etched by the inter-reaction between the remaining parts 536 of the outer layer 512, an inter-reaction which had been caused by heat, this object having parts protrusions 540 arranged in the same plane and corresponding to the parts 527 which had been irradiated and whose outer layer had been removed by the peeling operation following exposure of the element to light. 



   When the metal layer 512 is very thin, generally less than one micron thick, the etching of the metal layer, caused by heat, extends from surface to surface so that the finished object appears as shown in P1 in fig.  61. 



  consists of a metallic layer 512 provided with remaining parts 542 constituting a suitable metallic pattern in contrast to the perforations 544 due to etching from one surface to the other of the metallic layer. 



   Another sensitive element 510 'is shown schematically in section in FIG.  62.  This element is similar to the element described above, that is to say it comprises a metallic layer 512 provided with an adherent outer layer 514.  However, the metal layer 512 is provided, on its remaining free face, with a support or substrate 546 which can be made of any suitable material.  After exposure to incident light through a suitable mask 520, and after peeling off parts of the outer layer 514 and applying heat to the element as previously described, the object shown schematically in
C1 in fig.  63, which consists of a raised metal pattern 542, supported by a support or substrate 546. 

  Fig.  63 shows in C1 a finished article in which the metal layer 512 was originally thin enough that the heat-induced etching of the metal layer was carried out completely from its surface in contact with the remaining parts of the outer layer to on the surface of the substrate 546.  It is clear that the material of the substrate 546 should preferably be such that it reacts neither with the material constituting the outer layer 514, nor with the product resulting from the thermal reaction between the material of this outer layer with the metal. of the metal layer 512. 

  It is also obvious that the metal layer 512 must be thick enough not to be entirely etched from surface to surface during the heating process, so that the object obtained is substantially such as that A1 shown in FIG.  60 and which is provided with a suitable support or substrate. 

 

   Fig.  64 schematically represents an application of the invention for the establishment of an object provided with a metallic pattern in relief, such as a printed electric circuit.  The sensitive element 510 'comprising the metallic layer 512 disposed on a substrate 546 made of a non-conductive material, is provided with an outer layer 514, is exposed to incident radiation such as light 518, through a mask 520, comprising parts 524 which do not pass light and other parts 522 which pass light.  The combination of several parts which easily pass electromagnetic radiation comprising conductors 548 and terminals 550 provided with small parts 552 which do not pass light and the reason for which will be explained later. 

  After exposure to light, as shown in fig.  64, and after tearing off the parts of the layer 514 corresponding to the areas of the sensitive element 510 'which have been subjected to illumination through the mask, and after reaction under the effect of heat between the remaining parts of the outer layer and the metal layer 512 as described above in detail, the object D1 is obtained which consists of a printed circuit comprising metal conductors 554, according to the network shown
 in fig.  65.  This network is provided with terminals 556 having holes 558 for the connection of the conductors
 of an electrical or electronic component by welding
 or the like. 

  The circuit is printed on the surface of the
 substrate 546 which constitutes a support for this circuit and is in all points comparable to a printed circuit ob
 held by conventional processes which are more com
 folded. 



   Above, we explained in detail how in ex
 selectively and discontinuously posing a sen element
 susceptible to electromagnetic radiation the intensity of which
 is sufficient, as well as its duration, to produce a
 complete inter-reaction between the irradiated parts of the outer layer and the metallic layer of this element,
 it causes a deep etching of the layer
 metallic to said areas thus irradiated in a selective manner.
 tive and discontinuous. 

  In one embodiment, we pre
 also sees the formation of a metallic pattern in expo
 being an element sensitive to an image formed by a
 electromagnetic radiation and corresponding to a determined pattern and by following this exposure se
 selective and discontinuous of a second uniform exposure
 to electromagnetic radiation the intensity and duration of which are only sufficient to cause a slight
 inter-reaction between the metallic layer and the ex layer
 at the border between them, this reaction having
 the effect of significantly reducing the bond strength between them. 

  The remainder of the outer layer is then
 torn off from the metal layer, which preferably
 has been previously provided with a substrate, so that
   a metallic pattern is formed on this substrate, this pattern corresponding to the image which has been projected onto the element
 sensitive. 



   Referring more particularly to FIGS.  66 to 79, we see there another embodiment of a process
 to obtain a metallic pattern on a suitable substrate.  This is achieved using a sensitive element
 610 which mainly comprises a metallic layer 612 provided with an adherent outer layer 614
 in a material capable of interacting with the metal or
 metals of the metal layer 612 when subjected to electromagnetic radiation. 



   As described in detail above, the metal layer
 lic 612 of the sensitive element 610 shown in FIG.  66
 includes a metal either such or alloyed with another metal
 or other metals, or combined or mixed with an element
 ment or other elements.  The outer layer 614 which
 is deposited on the metal layer and adheres to it
 can include any of the materials described
 upper. 



   The sensitive element 610 of FIG.  66 includes in
 in addition to a weakly adhering substrate or support 616
 with the metal layer 612.  This support or substrate
 616 is not mandatory, but is often practical to provide a rigid support to the set of two layers formed of the metal layer 612 and the outer layer 614, given the small thickness of each of these layers which is l order from a few atoms to a few angstroms.  Thus, the support or substrate 616 provides mechanical strength to the element, which can thus be handled with a minimum of care.  A typical example of configuration for an element 610 would be, for example, a glass substrate 616 provided with a metallic layer 612 of silver and another layer comprising a strongly adherent outer layer 614 made of arsenic trisulfide. 



   The sensitive element 610 is exposed, as explained above, selectively and discontinuously, to incident electromagnetic radiation 618, such as intense white light, this through a mask 620.  This mask has a determined pattern consisting of parts such as those shown at 622 which easily pass incident radiation, while other parts 624 of the mask do not pass radiation.  The sensitive element 610 is thus exposed so that parts of the incident radiation 618 strike the outer layer 614 and cause an interaction between the material of the outer layer 614 and the metal of the metal layer 612, this at the areas 626 of the interface or intermediate layer, while other areas 628 are shielded from radiation. 

  It is clear that other means can be used to selectively and discontinuously expose the sensitive element 610 to incident electromagnetic radiation, for example by projecting onto the surface of the sensitive element an appropriate image corresponding to the pattern. this using well known projection means. 



   The sensitive element 610 is exposed to the incident electromagnetic radiation as explained previously, for a period sufficient to cause an interaction between the material of the layer 614 and the metal of the metallic layer 612 to thoroughly consume all the metal and parts. discontinuous of the metallic layer corresponding to the zones 626 which have been irradiated, this having the consequence of the formation of an inter-reaction product as shown at 630 in FIG.  67. 



   According to another embodiment, a substrate 632 made of a material such as glass, plastic, or metal foil, etc. , is arranged as shown in fig.  68, in contact with the outer surface of the outer layer 614.  The substrate 632 is provided, on its face 634 which is in contact with the outer surface of the outer layer 614, with an adhesive coating constituting a strong bond with the surface of this outer layer.  

  The only thing that is necessary is that the bond formed between the substrate 632 and the outer layer 614 is stronger than the bond formed between the metal layer 612 and the support 616, so that the assembly formed by the substrate 632 to which adhere the remaining parts 638 of the outer layer 614 and the remaining parts 636 of the metal layer 612, are easily separated from the support 616, as shown in FIG.  69. 



   The object obtained is represented at A2 in FIG.  69 and it comprises the substrate 632 which is provided with a metallic pattern formed by the remaining portions 636 of the metallic layer 612, the remaining portions 638 of the outer layer 614 remaining disposed between these metallic portions 636 and the substrate 632.  This object is useful in several applications.  For example, the object A2 can be used as a printing plate, the parts of the surface formed by the inter-reaction product 630 being susceptible to being wetted by an inking agent or the like, while the surface of the parts metallic 636 is substantially impermeable to wetting. 



   For other applications, it is preferable to remove the inter-reaction product 630, which removal can be carried out by simple mechanical means, such as tearing or brushing, or by chemical means such as dissolution of the interaction product in an aqueous solution of a base, the resulting object being that as shown in FIG.  70 in Ba.     It is provided with a raised metallic image which consists of the remaining parts 636 of the metal layer 612 which adhere to the remaining parts 638 of the outer layer 614, holes 640 being formed in the parts of the two layers which have interacted. upon exposure to the pattern constituting electromagnetic radiation. 



   According to another embodiment, the metallic layer 612 of the object B2 is arranged so as to adhere to a second substrate 642 having a face 644 which is in contact with the metallic layer, an adhesive forming an appropriate bond with the surface of the metal layer as shown in fig.  71.  The substrate 632 previously disposed on the surface of the outer layer 614 is in this case made of a material easily allowing electromagnetic radiation to pass, such a material possibly being glass, transparent plastic or the like. 



   The assembly thus formed is subjected to a second exposure to electromagnetic radiation 618 which strikes the side thereof which is provided with the transparent substrate 632, as shown in FIG.  72. 



  This irradiation is carried out for a period of time and with an intensity which are sufficient to cause a slight interaction between the remaining parts 638 and 636 of the outer layer 614 on the one hand and of the metal layer 612 on the other hand, this to cause at the interface or border between them, the formation of a small quantity of inter-reaction product as shown at 646 in FIG.  73.  This inter-reaction product causes a substantial decrease in the adhesive force between the remaining portions 638 and 636 of the outer layer 614 and the metal layer 612. 

  As a result of this reduction in the bonding force, the outer layer 614 can be separated or torn from the metal layer 612 which leads to obtaining the object Q of FIG.  74 which comprises a metallic pattern formed by the remaining parts 636 of the metallic layer 612 disposed on the substrate 642. 



   It can thus be seen that the embodiments of the method which are represented in FIGS.  66 to 70 provide other objects which mainly consist of a metallic pattern established on a substrate, remaining parts of the outer layer 614 being disposed between the metallic pattern and the substrate, while using the method according to fig.  66 to 74 a metallic pattern is formed on a suitable substrate, this metallic pattern being transferred from the original sensing element to a suitable support or substrate.  The sensitive element 610 of FIG.  66 can be considered as a universal element to obtain, by the transfer process described with regard to fig.  66-74, a suitable metallic pattern established on a suitable substrate. 

  For certain special applications, where the material and other characteristics of the substrate on which it is desired to pattern are known, the sensing element may be established as usual, and be provided, during its manufacture, with a substrate. suitable adhering to the metal layer. 



  Such a sensitive element is shown schematically in section at 611 in FIG.  75.  The sensitive element 611 is thus formed of a suitable substrate 642 to which adheres a metal layer 612 provided in turn with an outer layer 614 of a material capable of interacting with the metal of the metal layer 612 when is exposed to electromagnetic radiation. 



  To facilitate handling during the successive steps leading to obtaining a metallic pattern on the substrate 642 as will be explained in detail later, the element 611 is preferably provided with a layer 632 transparent to radiation and made up of made of a non-reactive material, such as clear glass, plastic or the like. 



   Sensitive element 611 is selectively and discontinuously exposed to electromagnetic radiation 618, as shown in FIG.  75, this by exposing it through a mask 620 or by projecting an appropriate image onto the element.  The exposure to electromagnetic radiation is carried out for a period of time and with an intensity which is sufficient to cause, at the irradiated areas of the element, an inter-reaction between the metal of the metallic layer 612 and the material of the outer layer 614 .  This causes a deep consumption of the metal of the metal layer, with formation of the inter-reaction product 630 at the location of the irradiated zones, as shown in FIG.  76. 

  To reduce the adhesive force between the metal layer 612 and the outer layer 614, the sensing element 611 is then uniformly exposed to incident radiation for a short period of time, to cause a very thin layer of product to form. 'inter-reaction 646 at the interface or boundary between them, this as shown in FIG.  77.  Thus, the outer layer 614 can be easily separated from the metal layer 612, as shown in FIG.  78.  In doing so, a metal pattern is left on the substrate 642 consisting of the remaining parts 636 of the metal layer 612 and parts of the inter-reaction product 630 corresponding to the areas which have been irradiated selectively and discontinuously, in order to obtain finally object D. 

  After removing the inter-reaction product 630, the object obtained appears as shown in ES in FIG.  79 and it consists of a metallic pattern formed by the remaining parts 636 of the metallic layer 612 deposited on the substrate 642. 

 

   In order to further simplify the process illustrated in FIGS.  75-79, the selective and discontinuous exposure to incident radiation, which is illustrated in fig.  75, can be effected through a mask or by projecting an image onto the sensing element 611, so that a small amount of radiation can uniformly strike the sensing element.  The selective and discontinuous parts are then irradiated with a greater intensity, these parts corresponding to the transparent parts 622 of the mask 620, all so that the second exposure illustrated in FIG.  76 is carried out at the same time as the selective and discontinuous exposure illustrated in FIG.  75. 



   It can thus be seen that the embodiments shown in FIGS.  66 to 79 allow to obtain patterns. metallic on any suitable substrate using a sensitive element, and without it being necessary to resort to complicated or delicate chemical treatments of the element after its exposure to the projected image of the pattern to be obtained. 



   Another embodiment provides methods for obtaining offset lithographic plates and the like using sensitive elements comprising:
 essentially a metallic layer, a second layer of a material capable, when exposed to electromagnetic radiation, of forming an inter
 reaction with the metal or metals of the metal layer
 metal, and a third layer forming a support. 



  These methods consist of exposing the sensitive element to
 an image projected onto it and which causes an inter
 selective and discontinuous reaction between the metal or
 metals of the metal layer and the material of the
 second layer, so that the reacted parts have different hydrophilic or oleophilic characteristics from the unreacted parts of the element. 



   With reference to the drawing and more particularly to
 fig.  80 to 86, fig.  80 is a schematic and exaggerated sectional view of a sensing element 710 comprising essentially three different layers substantially adhering to each other.  The first of these layers, which is the top layer, consists of a metallic layer 712 which adheres and which is in intimate contact with a second layer 714 made of a material capable, when exposed to electromagnetic radiation, of inter -React with the metal or metals of the metal layer 712, as explained previously in detail.  Layer 714 in turn adheres to a third support layer 716 made of a material incapable of interacting with second layer 714 even if it is exposed to electromagnetic radiation. 



     Z, a third layer 716 constitutes a mechanical support having the desired flexibility for the assembly of the two layers constituted by the metallic layer 712 and the layer 714, these layers 712 and 714 being substantially thin, of the order of a few atoms to a few angstroms, while the backing or third layer 716 is preferably on the order of a few thousandths of a centimeter (a few thousandths of an inch) thick. 

  This third layer is provided with a coating of arsenic trisulfide or arsenic pentasulfide, a few angstroms thick, which constitutes the second layer 714, which in turn is covered with a metallic layer 712 of silver or made of a silver-copper alloy, a few atoms or a few angstroms thick, and which is therefore thin enough to pass electromagnetic radiation such as intense white light, an electron beam or the like. 



   The sensitive element 710 is selectively and discreetly exposed to the incident electromagnetic radiation 718 which strikes the metal layer 712 through a mask 720 provided with an appropriate pattern consisting of parts, such as represented at 722 which allow easy passage. incident radiation, while other parts 714 do not pass radiation.  As a variant, the image can be projected by any suitable known means, onto the surface of the metallic layer 712 suitably, in order to form an appropriate image or pattern thereon. 



   The electromagnetic radiation selectively and discontinuously striking the surface of the layer 712 in areas such as 726, and transmitted to the boundary layer of the metallic layer 712 and the metallic layer 714, this to the selective and discontinuous areas corresponding to the irradiated surfaces 726 , which causes a selective and discontinuous interaction between the metal or! nets of the metal layer 712 and the material of the layer 714. 

  If the exposure is sufficient in duration and intensity, reacted zones form, corresponding to these irradiated zones which, as represented at 728 in FIG.  81, are constituted by an inter-reaction product resulting from - this selective and discontinuous inter-reaction between the metal or metals of the metal layer 712 and the material of the layer 714.  Other surface areas of the metal layer 712, as shown at 730, remain intact. The inter-reaction product of areas 728 has been found to exhibit general oleophilic properties, while the intact portions 730 which have no unreacted, the metal layer 712 exhibits hydrophilic characteristics. 

  The choice of the metal layer 712 and the material of the layer 714 determines the direction of humidification.  -As a result, the sensitive element 710 shown in FIG.  81 can be used as an offset lithographic plate or the like without undergoing other treatments.  This is done as is well known in the art of offset lithographic plate printing.  by fixing a plate such as that shown in FIG.  81 on a drum in a printing machine, wetting its surface with a film of water and then inking the surface of the plate.  The hydrophilic areas 728 of the plate absorb water during the wetting operation and thus repel ink during the inking operation. 

  The parts 730 of the plate which cannot be wetted accept ink during the inking operation, due to their oleophilic qualities, and the lithographic plate can thus be used for batchwise and selectively inking a belt. printing or the like, which in turn is used to print directly onto a material receiving the print. 



   It has been found that when the metal layer 7I2 is very thin, from a few atoms to a few angstroms, and is made of a metal such as silver, the resulting lithographic plate is provided.  after selective and discontinuous exposure to electromagnetic radiation in the form of an image projected onto the surface of the sensitive element 510, of selective and discontinuous areas of reacted materials 728 which are oleophilic, while areas 730 of the metallic layer 712 which have not reacted, constitute a hydrophilic medium.  

  The reason for such behavior may be a consequence of the thin film structure and if, before exposure, the surface is cleaned and coated with gum arabic, the hydrophilicity of the thin metal layer 712 is increased, which produces an offset lithographic plate in which the ratio of oleophilicity to hydrophilicity of the exposed areas is greater than the ratio of oleophilicity to hydrophilicity of unexposed areas, while thicker metal layers 712 can be established which lead to the opposite result, as mentioned earlier. 



   Example I
 A sensitive element 710 consists of a support 716 of aluminum foil covered with a layer 714, a few angstroms thick, of arsenic trisulfide, the latter layer itself being covered with a metallic layer 712 of silver , 1 to 2 angstroms thick.  After selective and unobtrusive exposure to electromagnetic radiation, the resulting lithographic plate shows hydrophilic properties with respect to the areas which have been irradiated and oleophilic properties with respect to the areas which have not been irradiated. 



   Example he
 A sensitive element 710 consisting of an aluminum support 716 covered with a layer 714 of arsenic pentasulfide, a few angstroms thick, is covered with a metallic layer 712 of silver a few atoms thick, and prepared before being exposed to electromagnetic radiation, by cleaning the silver surface with a weak solution of nitric acid and coating this surface with gum arabic.  After exposure, the areas of the silver surface which have not reacted exhibit hydrophilic properties, while the areas of the surface which have simultaneously undergone the reaction exhibit oleophilic properties. 



   Example 111
 An element 710 consisting of an aluminum support 716 covered with a layer 714 of arsenic pentasulfide, a few angstroms thick, which in turn is covered with a metal layer 712 of copper, a few atoms to a few angstroms in thickness, after selective and discontinuous exposure to electromagnetic radiation, exhibits reacted areas which exhibit hydrophilic properties, while unreacted copper areas exhibit oleophilic properties. 



   Fig.  82 schematically shows, in section, a variant of sensitive element 710 ', which is provided with a support allowing radiation to pass or third layer 716, which may consist of a thin transparent layer made of a plastic material.  With such an arrangement of the elements, it is possible to discontinuously and selectively expose the sensitive element 710 'to electromagnetic radiation striking the surface of the support or third layer 716, this as shown in FIG.  82.  The object obtained is an offset lithographic plate, as shown in fig.  83, which in all other respects is substantially similar to the offset lithographic plate of FIG.  81. 



   Fig.  84 shows schematically and in section, a sensitive element 710 "which comprises a first layer 714, made of the same material as the layer 714 of the element shown in FIG.  80 or in fig.  82, this first layer 714 adhering to a metallic layer 712 which in turn adheres to a support or third layer 716. 



   The first layer 714 is of any of the materials listed with respect to the embodiment.
 shown in fig.  80, such as for example arsenic trisulphide or arsenic pentasulphide, the metal layer 712 possibly being any of the metals or mixture of metals indicated above, such as rare or the silver-copper alloy, the third layer or support layer 716 which may be of any suitable material, preferably aluminum. 



   After selective and discrete exposure to electromagnetic radiation 718 through a mask 720, as shown in FIG.  84, or alternatively by projection of an electromagnetic image projected onto the outer surface of the first layer 714, the exposed sensitive element 710 "is, as shown schematically in section in FIG.  85, provided with surface areas 728 formed by the inter-reaction product resulting from the reaction between the metal or metals of the metal layer 712 with the material of the layer 714, the surface areas 732 of the layer 714 do not experiencing no reaction. 



  As regards the difference between the ratio of the hydrophilicity and the oleophilicity of the zones 728 which have undergone the reaction and the ratio between the hydrophilicity and the oleophilicity of the zones 732 which have not undergone the reaction, the element represented in fig.  85 can be used as an offset lithographic plate or the like, but experience has shown that it is preferable for most applications to remove the reacted portions 728 and the remaining portions of the layer 714. 

  This can be done by mechanical stripping as explained in detail above, or alternatively, by washing the element exposed in FIG.  85 in a mild solution of sodium hydroxide, which dissolves the remaining unreacted portions of layer 714 and the reacted portions 728, thereby producing the offset lithographic plate shown in fig.  86. 



  This only comprises the support 716 and the remaining parts 734 which have not undergone any reaction from the metallic layer 712.  Removal of the reacted portions 728 and remaining portions of the first layer 714 is facilitated by brushing the surface of the plate or by spraying with a steam jet. 



   The offset lithographic plate of FIG.  86 is thus constituted by a bimetallic plate comprising a metal support 716, for example of aluminum, parts of its surface of which are covered or masked by another metal such as silver, these parts being defined by the remaining parts 734 of the metal layer 712.  Although the exaggerated representation of fig.  86 shows the exposed areas 736 of the supporting metal layer 716 as being recessed relative to the surface of the areas 734 of the metal layer 712, it should be shown that this level difference is in fact only of the order of a few atoms or angstroms.  The exposed areas 736 of the supporting metal layer 716 are generally hydrophilic, while the surface of the remaining areas 734 of the metal layer 712 are generally oleophilic.  

  The hydrophilicity property of the exposed surface areas 736 of the support 716 can be increased significantly by first rendering the surface of the metal support 716 granular, before applying the metal coating or layer 712 thereon during the manufacture of the plate. sensitive.  This preliminary granulation of the surface of the metal support 716 can be carried out by brushing, by anodization, or by granulation using balls and it has the effect of increasing the inter-layer adhesion between the support 716 and the metal layer. 712. 



   Example IV
 A sensitive element 710 ', comprising a granular support 716 of aluminum provided with a metallic layer of silver 712, a few angstroms thick
 sor, is in turn provided with an outer layer 714
 made of arsenic trisulfide, also a few angstroms thick, and cleaned in a mild solution of sodium hydroxide after being selectively and discontinuously exposed to electromagnetic radiation. 



  It has unreacted silver parts exhibiting oleophilic properties and granulated aluminum parts corresponding to the irradiated parts and having undergone radiation, these parts having so-called hydrophilic properties. 



   Example V
 A sensitive element 710 'consisting of a granular aluminum support 716 provided with a metallic layer 712 of silver, a few angstroms thick, which in turn is covered with a layer 714 of copper chloride also of a few angstroms thick, is discreetly and selectively exposed to electromagnetic radiation.  The exposed element is used as a lithographic plate by being placed in a printing press, and the washing with water before inking the plate is sufficient to rid the unreacted parts of copper chloride and the resulting product from the plate. 'inter-reaction between copper chloride and silver.  The remaining areas of the silver are oleophilic, while the areas of granular aluminum corresponding to the irradiated areas which have undergone the reaction are hydrophilic. 



     It is clear that the offset lithographic plates which have the configuration according to FIG.  86, can be stored after use, for a very long period without being damaged, since they consist exclusively of two superimposed metallic layers which cannot interact with each other. 

  Although the lithographic plates as illustrated in Figs.  81, 83 to 85, always comprise the pair of layers capable of reacting with each other, that is to say the metallic layer 712 and the layer 714, the inking of the surface of the metallic layer 712 of FIG.  81 and the surface of layer 714, fig.  85, ass
 provide a covering opaque to radiation, which makes it possible to store the plates according to the usual method, for example by placing these plates in an envelope and in a drawer, which allows them to be stored indefinitely.  For practical reasons, the same process of storing the plates in an envelope and in a drawer can be used to advantage for them.
 plates according to fig.  83, although it is possible to recou
 screw the surface of the transparent support 716 in order to
 make it non-transparent, if desired. 



   It can thus be seen that the methods described make it possible to establish lithographic plates in offset and ana
 logues from elements sensitive to radiation, without the need for chi
 complicated or delicate elements, this after
 exposure to appropriate radiation images. 



   It has also been discovered that certain materials of
 described earlier in the description as being capable of reacting with a metallic layer under the effect of a
 electromagnetic radiation also have physical and chemical characteristics different from
 those of the same material which have not been subjected to electromagnetic radiation.  Such a change of pro
 chemical and physical properties means that
 the ratio between the hydrophilicity and the oleophilicity of the zones
 exposed is different from this ratio for areas not
 exhibited. 

  In addition, the exposed and unexposed areas show differences in solubility in particular solvents, which significantly increases the differences between the ratios of hydrophilicity to oleophilicity and oleophilicity to oleophilicity. the hydrophilia of these. 



   As explained above in the present description, the sensitive elements, shown as a whole at 910 in FIGS.  87 to 96 of the drawing, mainly comprise two different layers adhering one to the other.  One of the layers, for example layer 912, fig.  87, is a metallic layer which adheres to and is in intimate contact with a second layer 914 of a material which is capable, when exposed to electromagnetic radiation, to inter-react with the metal or metals of the metallic layer 912.  For certain applications, it is advisable to provide a substrate or support for the sensitive element 910, this support consisting of a rigid or flexible material such as a plate or a sheet of metal, a sheet of plastic, paper or cardboard. , etc. , this as explained above in the present description. 



   As previously indicated, the metallic layer 912 of the sensing element 910 comprises a metal, either alone or alloyed with another metal or with other metals, or combined or mixed with an element or other elements.  The metallic layer 912 can thus comprise any of several common metals such as silver, copper, zinc, colombium, lead, iron, aluminum, chromium, nickel and the like.  The second layer 914 can comprise any one of the materials mentioned above in the description.  Such materials include ternary materials containing arsenic, sulfur and iodine, or arsenic, sulfur and bismuth, for example. 

  The material constituting the second layer 914 can also be constituted by an element of a group of binary materials such as a metal halide, a sulphide, a selenide, or a telluride, a monosulphide, a disulphide, a trisulphide and a pentasulphide. of arsenic, and a sulfur-selenium mixture.  As a variant, the material constituting the layer 914 can be constituted by any one of several following simple elements: a halogen such as iodine, arsenic, sulfur, selenium, tellurium, thallium.  The two layers 912 and 914 are thin, on the order of a few atoms to several angstroms in thickness, generally. 



   As shown in fig.  87, the sensitive element 910 can be exposed to the action of electromagnetic radiation 916 through a suitable mask 918 provided with parts.  as shown at 920, which easily pass incident electromagnetic radiation, and parts, as shown at 922, which do not pass electromagnetic radiation.  As a result, the surface of the sensing element 910 is selectively and discontinuously exposed to incident electromagnetic radiation 916, so that some areas thereof, as shown at 924, are irradiated, while other areas .  as translated in 926 and which correspond to parts 922 of the mask which are not transparent, are protected against radiation.  

  The face of the sensitive element 910 which is subjected to the action of the electromagnetic radiation 916, may be the face formed by the second layer 914. 



  The latter can be either in solid, liquid or gas form.  Alternatively, the metallic layer 912 may be subjected to the action of incident electromagnetic radiation, selectively and discontinuously, provided that this metallic layer 912 is transparent to the electromagnetic radiation used, so that an inter- selective and discontinuous reaction is formed at the border between the two layers, this between the materials of these two layers and at the irradiated zones.  The incident electromagnetic radiation can be in the invisible region or in the visible region of the spectrum and consist of either coherent light or incoherent light, monochromatic light or the like. 

  The source of incident electromagnetic radiation, which is not shown, may be an incandescent lamp, an electric arc, a laser, etc.  It can also be constituted by an X-ray source or by a radioactive isotope emitting gamma rays or the like. 



   Alternatively, an image may be projected onto the surface of the sensitive element 910, as shown in FIG.  88, by any suitable means such as a projector Q28 which comprises an illumination source not shown and which is arranged to project an image using a lens system 930.     This projector can be a sliding projector of a well-known type, a continuous strip projector, an enlarger.  an opaque projector or the like. 



   -Fig.  89 schematically shows a device for exposing a sensitive element 910 to an energy beam such as an ion or electron beam. 



  This device consists, for example, of a bell or other container 932 provided with a removable base 934 and which can be closed in a sealed manner.  A vacuum source 936 is connected to the interior 938 of the bell or container 932 in order to maintain a low atmospheric pressure, of the order of 10- "to 10-8mm of mercury for example.  Alternatively, for some applications, the interior 938 of the bell or container 932 may be filled with an inert gas. 



   The bell or container 932 is provided, in its interior, with an ion or electron source 940, which comprises a beam forming element connected to means 942 for controlling the beam.  Such an arrangement is conventional and is well known in the art of cathode ray tubes and in the art of electron microscopes. 



   Thanks to the arrangement shown in FIG.    89, the sensitive element arranged on the base 934 and inside 938 of the bell 932, is subjected to ionic or electron bombardment by the ionic or electron beam generated by the source 940 under the control of the control device 942 of the beam.  The sensitive element 910 can be subjected to such bombardment by the ionic or electron beam through a mask, not shown, so as to produce a discontinuous and selective irradiation on the appropriate areas of the element. 

  Preferably, the sensitive element 910 can also be subjected to ion or electron beam bombardment selectively and discontinuously by scanning the surface of the element with a thin beam of ions or electrons modulated in intensity and deflected under the control of the controller 942, as in conventional systems used in CRT Cathode Rays Tube - Cathode Ray Tube - and in the art of recording information. 

  As shown in fig.  92, the scanning of the surface of the sensing element 910 can be performed using a narrow beam 944 of ions or electrons, this beam being adequately deflected to scan lines 946 along the line. surface of the element, the beam being further modulated, in order to interrupt the flow of ions or electrons so that it does not strike the surface of the sensitive element in areas which must not be exposed.  The ions or electrons can, on the other hand, strike the surface of the element in the areas which must be exposed.  The beam control and deflection system moves the beam so as to scan each successive line 946. 



   Fig.  90 schematically represents a device similar to that of FIG.  89 in which, however, the sensitive element 910 is disposed outside the container 932, which comprises a face 948 arranged to pass the beam.  Such a device can be constituted by a Leonardo tube which is similar to the conventional cathode ray tube, but is provided with a sufficiently thin face 948 and of a material such as titanium, in order to allow the electrons to pass while maintaining the vacuum required in the tube. 



   Fig.  91 schematically represents a device similar to that of FIG.  90, the element 910 being however constituted in the form of an elongate and foldable member as described above with reference to FIGS.  1 to 8. 



  Such a sensitive, elongated and foldable element 910.  may be a paper backing provided with a thin layer of a material such as arsenic trisulfide or arsenic pentasulfide, capable of reacting with the metal when exposed to electromagnetic radiation. 



  Thanks to the device of FIG.  91, the sensitive element 9i0 can be advanced from a conventional supply coil 950, to another conventional coil 952, this by means of a supply mechanism not shown.  The information can be recorded on the surface of the sensing element continuously, or intermittently, as is well known in the art of recording and storing information. 



   Fig.  92 schematically shows a sectional view through a sensing element 910, after it has been selectively and discontinuously exposed to electromagnetic radiation.  The non-irradiated areas, as shown in 954, for example, are not changed, while in the 956 areas, subjected to irradiation, an inter-reaction occurs between the metal or metals of the metal layer 912 and the material of layer 914, such that the resulting inter-reaction product 958 exhibits physical and chemical characteristics different from those of the remaining intact portions of metal layer 912 and layer 914. 



  In fig.  93, the element 910 which has been exposed is shown after having undergone an irradiation which caused a complete inter-reaction at the irradiated zones 956, between the different components of the two layers, while FIG.  94 schematically shows the results obtained by exposing a sensitive element 910 to electromagnetic radiation the intensity of which is variable or, alternatively, the duration of which is variable.  Areas such as 960 were exposed for a time and with sufficient intensity to cause a complete and irreversible reaction between the components of the two layers, while in areas 962 and 964 the irradiation was carried out with intensity and intensity. insufficient time to elicit a full reaction.  

  Accordingly, in fig.  94, the chemical and physical characteristics of zones 960, 962 and 964 are not only different from the chemical and physical characteristics of intact zones 954, but differ from each other.   



   Such differences in chemical and physical characteristics result in differences in chemical reactivity with regard to, for example, suitable solvents.  Thus, the irradiated areas can be dissolved selectively leaving the non-irradiated areas intact, or the irradiated areas and the non-irradiated areas of one of the layers can be dissolved at will. 



   Changes in physical characteristics may relate to electrical, thermal, optical properties, or may relate to the possibilities of humidification.  This latter property, which has been described above, makes it possible to obtain, using a sensitive element as described, lithographic plates and the like, comprising zones provided with different oleophilic and hydrophilic characteristics.  Changes in electrical characteristics include, among other things, changes in the specific resistivity of materials in areas that have been selectively and discontinuously exposed to electromagnetic radiation. 



  Such changes in resistivity make it possible to obtain, as explained in detail above, printed electrical circuits comprising electrical elements forming an integral part of the circuit, such as resistors and capacitors of determined value.  Changes in specific resistivity also allow information to be stored which is recorded on the element.     appropriately, and are read by differentiating between the resistivity of the different zones, analogous to the storage system using magnetic tapes or perforated tapes. 



   Other physical changes that sensitive elements undergo as a result of exposure to electromagnetic radiation are optical in nature.  For example, a sensitive element, such as that shown in FIG.  95, and which consists of a metallic layer 912, is made, for example, of any of the metals listed above, such as silver, and is provided with a layer 914, of a material such as, for example, trisulfide of Arsenic, or arsenic pentasulfide, is prepared so that the thickness of the metal layer 912 allows the passage of 1 µl /, for example, of a determined electromagnetic radiation, such as ordinary light. 

  After exposure to electromagnetic radiation for a determined period and with a determined intensity, the inter-reaction between the metal of the metallic layer 912 and the material of the layer 914 modifies the element 910 so, for example, that it leaves pass 50 "/ 0 of the write-off.  We see that we can establish filters.  As a variant, these modifications of the optical qualities of the sensitive element 910 can be used advantageously for the optical recording and the optical reading of information stored in the sensitive element according to an appropriate code. 

  By discontinuously and selectively exposing to suitable electromagnetic radiation representing an appropriate pattern and for a time and with sufficient intensity to cause an interaction between the materials of the two layers, an element can be obtained as shown schematically in FIG. .  96 where intact areas are not transparent, while exposed areas 966 readily pass radiation. 



      CLAIM I
 Process for the manufacture of an object by photochemical means, characterized in that an element having a metallic layer of which one of the faces is in contact with a second layer of an inorganic material comprising at least one of the chemical elements is used. following: a halogen, sulfur, arsenic, selenium, tellurium, thallium, in that part of this assembly formed of two different layers is subjected to radiation, so as to form a product of interaction in said layers and in that the element thus irradiated is subjected to a finishing operation. 



   CLAIM II
 Element for carrying out the process according to Claim I, characterized in that it has a metal layer, one of the faces of which is in contact with a layer of a non-organic material comprising at least one of the following chemical elements: a halogen, sulfur, arsenic, selenium, tellurium, thallium, this element being capable of forming an interaction product when it is subjected to radiation. 



   CLAIM III
 Object obtained by the process according to claim I. 



   SUB-CLAIMS
 1.  A method according to claim I for establishing a metallic pattern in which the metal layer (14, 420, 512, 612, 712) adheres on its other side to a substrate (12, 424, 546, 616, 716) , characterized in that imaging radiation is applied to the inorganic layer of said element (16, 422, 514, 614, 714) to cause selective and discontinuous formation of said interaction product (32, 430, 526) , 630, 728) in predetermined zones of the border between said first and second layers by deep reaction of parts of said first layer and in that said substrate is removed. 



   2.  Process according to sub-claim 1, characterized in that said interaction product is removed. 



   3.  Method according to sub-claim 1, characterized in that said layer 614 is fixed to a support (632). 



   4.  Method according to sub-claim 2, (fig.  71-74), characterized in that said first layer (612) is fixed to a support (642), then said element is uniformly exposed to electromagnetic radiation to cause interaction in the remaining areas of the boundary between said first and second layers which is sufficient only to reduce the adhesion between them, and in that said second layer (614) is removed. 



   5.  Method according to sub-claim 1, (fig.  71-74), characterized in that said first layer (612) is fixed to a support (642), then said sensitive element is exposed to electromagnetic radiation to cause interaction at the remaining areas of the border between said first and second layers which is sufficient to reduce the adhesion between them, and in that said second layer (614) is removed. 

 

   6.  Method according to sub-claim 5, (fig.    78-79).    



  characterized in that the interaction product (630) is removed. 



   7.  Method according to sub-claim 3, (fig.  71-74), in which said support (632) allows the passage of said electromagnetic radiation, characterized in that said first layer (612) is fixed to a second support (642), said element is exposed uniformly to a electromagnetic radiation to produce an interaction in the remaining areas of the boundary between

** ATTENTION ** end of DESC field can contain start of CLMS **. 



   


    

Claims (1)

** ATTENTION ** start of field CLMS can contain end of DESC **. Such differences in chemical and physical characteristics result in differences in chemical reactivity with regard to, for example, suitable solvents. Thus, the irradiated areas can be dissolved selectively leaving the non-irradiated areas intact, or the irradiated areas and the non-irradiated areas of one of the layers can be dissolved at will. Changes in physical characteristics may relate to electrical, thermal, optical properties, or may relate to the possibilities of humidification. This latter property, which has been described above, makes it possible to obtain, using a sensitive element as described, lithographic plates and the like, comprising zones provided with different oleophilic and hydrophilic characteristics. Changes in electrical characteristics include, among other things, changes in the specific resistivity of materials in areas that have been selectively and discontinuously exposed to electromagnetic radiation. Such changes in resistivity make it possible to obtain, as explained in detail above, printed electrical circuits comprising electrical elements forming an integral part of the circuit, such as resistors and capacitors of determined value. Changes in specific resistivity also allow information to be stored which is recorded on the element. appropriately, and are read by differentiating between the resistivity of the different zones, analogous to the storage system using magnetic tapes or perforated tapes. Other physical changes that sensitive elements undergo as a result of exposure to electromagnetic radiation are optical in nature. For example, a sensitive element, such as that shown in FIG. 95, and which consists of a metallic layer 912, is made, for example, of any of the metals listed above, such as silver, and is provided with a layer 914, of a material such as, for example, trisulfide of Arsenic, or arsenic pentasulfide, is prepared so that the thickness of the metal layer 912 allows the passage of 1 µl /, for example, of a determined electromagnetic radiation, such as ordinary light. After exposure to electromagnetic radiation for a determined period and with a determined intensity, the inter-reaction between the metal of the metallic layer 912 and the material of the layer 914 modifies the element 910 so, for example, that it leaves pass 50 "/ 0 of the radiation. It is thus seen that filters can be established. Alternatively, these modifications of the optical qualities of the sensing element 910 can be used advantageously for the optical recording and the optical reading of information stored in the sensitive element according to an appropriate code. By discontinuously and selectively exposing to suitable electromagnetic radiation representing an appropriate pattern and for a time and with sufficient intensity to cause an interaction between the materials of the two layers, an element can be obtained as shown schematically in FIG. . 96 where intact areas are not transparent, while exposed areas 966 readily pass radiation. CLAIM I Process for the manufacture of an object by photochemical means, characterized in that an element having a metallic layer of which one of the faces is in contact with a second layer of an inorganic material comprising at least one of the chemical elements is used. following: a halogen, sulfur, arsenic, selenium, tellurium, thallium, in that part of this assembly formed of two different layers is subjected to radiation, so as to form a product of interaction in said layers and in that the element thus irradiated is subjected to a finishing operation. CLAIM II Element for carrying out the process according to Claim I, characterized in that it has a metal layer, one of the faces of which is in contact with a layer of a non-organic material comprising at least one of the following chemical elements: a halogen, sulfur, arsenic, selenium, tellurium, thallium, this element being capable of forming an interaction product when it is subjected to radiation. CLAIM III Object obtained by the process according to claim I. SUB-CLAIMS 1. Method according to claim I for establishing a metal pattern in which the metal layer (14, 420, 512, 612, 712) adheres by its other face to a substrate (12, 424, 546, 616, 716), characterized in that an image forming radiation is applied to the inorganic layer of said element (16, 422, 514, 614, 714) in order to cause the selective and discontinuous formation of said interaction product (32, 430 , 526, 630, 728) in predetermined areas of the border between said first and second layers by deep reaction of parts of said first layer and in that said substrate is removed. 2. Method according to sub-claim 1, characterized in that said interaction product is removed. 3. Method according to sub-claim 1, characterized in that said layer 614 is fixed to a support (632). 4. Method according to sub-claim 2, (fig. 71-74), characterized in that said first layer (612) is fixed to a support (642), then said element is exposed uniformly to electromagnetic radiation. to cause an interaction in the remaining areas of the boundary between said first and second layers which is sufficient only to reduce the adhesion between them, and in that said second layer (614) is removed. 5. Method according to sub-claim 1, (fig. 71-74), characterized in that said first layer (612) is fixed to a support (642), then said sensitive element is exposed to electromagnetic radiation to cause an interaction at the remaining areas of the border between said first and second layers which is sufficient to reduce adhesion between them, and in that said second layer (614) is removed. 6. Method according to sub-claim 5 (fig. 78-79). characterized in that the interaction product (630) is removed. 7. Method according to sub-claim 3, (fig. 71-74), wherein said support (632) allows the passage of said electromagnetic radiation, characterized in that said first layer (612) is fixed to a second support. (642), said element is uniformly exposed to electromagnetic radiation to produce an interaction in the remaining areas of the boundary between said first and second layers which is sufficient only to reduce the adhesion between them and in that said second layer (614) is removed. 8. Method according to sub-claim 4, wherein said support (.642) allows electromagnetic radiation to pass, characterized in that said second layer (614) is fixed to a second support (632), in that uniformly exposes said element to electromagnetic radiation to cause interaction in the remaining areas of the boundary between said first and second layers which is sufficient only to reduce adhesion between them, and to remove said second layer (614 ). 9. Method according to sub-claim 1, characterized in that said first layer is a metal belonging to the group comprising silver, nickel, copper, colombium, lead, iron, aluminum, zinc, chromium and mixtures thereof. 10. The method of sub-claim 1, characterized in that the material of said second layer is selected from a group comprising metal halides, metal sulfides, metal arsenides, metal selenides, metal tellurides and mixtures of those. -this. 11. The method of sub-claim 1, character ized in that said material of said second layer is selected from a group consisting of arsenic trisulfide, arsenic pentasulfide and mixtures thereof. 12. The method of claim I (fig. 72-79) for obtaining a metal pattern on a support, characterized in that one exposes discontinuously and selectively by projecting an image of the pattern to be obtained, the surface d 'an electromagnetic radiation sensitive element comprising a support (642) with said metallic layer (612) adhering thereto, said metallic layer being provided with said second layer (614) adhered thereto strongly, in that said element is then exposed uniformly to electromagnetic radiation to cause interaction in the remaining areas of the boundary (646) between said metallic layer and said second layer, this exposure being sufficient only to reduce the adhesion between these layers, in that said second layer is separated from said layer metallic, and in that said product of inter action so as to form a pattern on said support metal adhering to the support which is a reproduction metallic tion of said image. 13. The method of sub-claim 12, (fig. 72 79). characterized in that said second layer is separated of said support by means of a member provided with a cover adhesive bond forming with the outer surface of said second layer a bond that is stronger than membership reduced between said second layer and said metal layer tallic. 14. The method of sub-claim 13, character ized in that said metal layer is an ap metal leaving to a group comprising silver, nickel, copper, colombium, lead, iron, aluminum, zinc, chromium and mixtures thereof. 15. The method of sub-claim 13, character ized in that the material of said second layer is selected from a group comprising the halides of metal, metal sulphides, metal arsenides, metal selenides, metal tellurides, and mixtures thereof. 16. The method of sub-claim 13, characterized in that the material of said second layer is selected from a group comprising arsenic trisulfide, arsenic pentasulfide and mixtures thereof. 17. The method of claim I (fig. 56-65), for establishing a metal pattern in relief using an element sensitive to electromagnetic radiations and comprising said metal layer (516) covered with said second adherent layer (514) of a material capable of interacting, when exposed to electromagnetic radiation, with said metallic layer so as to reduce the adhesion between said second layer and said metallic layer, characterized in that an image is projected in the form of electromagnetic radiation of the pattern to be reproduced on the sensitive element so as to reduce the adhesion force in predetermined zones between the second layer and the metallic layer and which have been struck by said electromagnetic radiation, in that parts (534) of said second layer corresponding to said areas of which adhesion has been reduced are removed while the other parts (536) remain in place, adhering to said metal layer and heating said metallic layer to cause an interaction between the remaining portions of said second layer and said metallic layer, which has the effect of deeply etching said metallic layer at the places covered by said remaining portions of said second layer. 18. The method of sub-claim 17, characterized in that the material of said second layer is selected from a group comprising metal halides, metal sulfides, metal arsenides, metal selenides, metal tellurides. , arsenic trisulfide, arsenic pentasulfide, mixtures of lead and iodine and mixtures of arsenic sulphides and halides. 19. The method of sub-claim 17, characterized in that said metallic layer comprises a metal selected from a group comprising silver, copper, nickel, colombium, lead, iron, zinc, chromium and aluminum. 20. The method of sub-claim 17, characterized in that said metal layer is carried by a different substrate (546). 21. Method according to sub-claim 17, characterized in that said parts of the second layer are removed by means of a member (530) provided with an adhesive covering (532) forming with said second layer a bond. stronger than the reduced adhesion between said second layer and said metallic layer, said bond being weaker than the normal strength of adhesion between said second layer and said metallic layer. 22. The method of claim I (fig. 34-44), for establishing an object having an image in relief, characterized in that a radiation determining an image is applied to said sensitive element to cause formation. selective and discontinuous of said interaction product (430) in predetermined zones of the boundary between said first (420) and second (422) layers to selectively and discontinuously reduce the adhesion therebetween, by removing portions (438) of said second layer which correspond to the boundary areas where the Adhesion has been reduced, this so as to expose said first layer in those areas (442), and in that said areas of said first layer which have been exposed are electrically treated. 23. The method of sub-claim 22, characterized in that said areas of the first layer are treated electrically so as to obtain an electric plating (452). 24. The method of sub-claim 23, (fig. 41), characterized in that said sensitive element is subsequently exposed uniformly to electromagnetic radiation to cause the formation of said interaction product (454) at the remaining zones of. the border between said first and second layers to reduce the adhesion between them, and in that the remainder of said second layer. 25. The method of sub-claim 23, character ized in that said element is subsequently exposed uniformly susceptible to electromagnetic radiation to cause the formation of said interaction product at the remaining portions of said first and second layers to deeply consume the remainder of said first layer at said areas, and in that said interaction product is removed . 26. Method according to sub-claim 22, character ized in that said zones of said first layer are treated electromagnetically by electrochemical erosion. 27. Method according to sub-claim 26, (fig. 43), characterized in that said first layer is eroded. electrochemically completely in depth at the places (456) where it was exposed. 28. A method according to sub-claim 26, character ized in that said sensitive element is then exposed uniformly to electromagnetic radiation to cause the formation of said interaction product to remaining areas of the border between said first and second layers to reduce adhesion between them, and in that the remainder of said second layer is removed. 29. The method of claim I, (fig. 19-33) for the establishment of an electrical component comprising a organ with lower resistivity juxtaposed with an organ of higher resistivity, this using a sensitive element radiation comprising at least said first metal layer (212) defining said member at more low resistivity and said second adherent layer (214) of a material defining said more resistive member high and capable, when exposed to radiation electromagnetic to interact with the metal of said first layer so as to form an inter action having composition and electrical resistance intermediate between the resistances of said metal and said material, characterized in that one exposes a part of said element to electromagnetic radiation inci tooth to cause the formation of a pre determined of said interaction product exhibiting said intermediate resistivity, and in that one protects in a permanent another part of said element against the ra incident electromagnetic diation to prevent formation of said interaction product. 30. The method of sub-claim 29, character ized in that the metal of said first layer belongs to a group comprising silver, nickel, copper, colombium, lead, iron, aluminum, zinc, chromium and mixtures thereof . 31. Method according to sub-claim 30, characterized in that the material of said second layer is selected from a group comprising metal halides, metal sulphides, metal arsenides, metal selenides, metal tellurides. , arsenic trisulfide, arsenic pentasulfide and mixtures thereof. 32. The method of sub-claim 29, characterized in that the electrical characteristics of said element are continuously monitored during the exposure of the latter to said electromagnetic radiation, and in that said exposure is interrupted when characteristics predetermined values of said element are obtained. 33. The method of claim I (fig. 24 and 3032), for establishing an electrical circuit comprising at least one resistance and one capacitor, electrical connections between them and input and output terminals, in which there is uses an element whose first layer (212) rests on one side of a dielectric (260) provided with a metallic layer (262) on the other side, characterized in that areas of said element are exposed to radiation electromagnetic projected onto the latter according to a predetermined pattern to cause the formation of said interaction product consuming in depth all the metal of said first metal layer in said zones, the other zones are simultaneously protected against said electromagnetic radiation, this according to a determined pattern in order to leave in said first layer a conductive electrical network defining said resistance, a first plate of said capacitor and electrical connections between them, a first part of said other zones corresponding to said resistance is partially and simultaneously exposed for causing the formation of said interaction product with deep consumption of a part of said first layer to give said resistance a predetermined value, simultaneously exposing a second part of said other areas corresponding to said first plate of said capacitor to cause the formation of said capacitor interaction product deeply consuming said first metal layer, in order to adjust the surface of said plate to obtain a predetermined capacitance for said capacitor, electrical terminals are attached to parts of said first metal layer and to said metal layer to form said input and output terminals, and the other parts of said element are permanently protected from said incident electromagnetic radiation to prevent interference therein. formation of said interaction product. 34. Method according to sub-claim 33, character ized in that the metal of said first layer belongs to a group comprising silver, nickel, copper, colombium, lead, aluminum, zinc, chromium and mixtures thereof. 35. The method of sub-claim 34, character ized in that the material of said second layer is selected from a group comprising the halides of metal, metal sulphides, metal arsenides, metal selenides, metal tellurides, arsenic trisulfide, arsenic pentasulfide and mixtures of these. 36. Method according to sub-claim 33, characterized in that the electrical quantities of said circuit are continuously monitored during re-exposure to said electromagnetic radiation, and in that said exposure is interrupted when determined values are obtained for them. electrical quantities. 37. The method of claim I, (fig. 1-8), for obtaining a metallic reproduction of an image in which element comprises a flexible sheet (12) made of a material belonging to a group comprising paper, cardboard, plastic on which said metallic (14) and inorganic (16) layers are arranged, the interaction product having a composition and physical characteristics different from those of said inorganic material and of said metal, characterized in that 'said element is selectively exposed to radiation forming an image, this in a manner sufficient to cause, selectively and discontinuously, an inter-reaction between said metal and said non-organic material, this with formation of said inter-reaction product . selectively and batchwise and depleting said metal, and removing said inter-reaction product. 38. The method of sub-claim 37, characterized in that the metal of said layer belongs to a group comprising silver, nickel, copper, co Iombium, lead, iron, aluminum, zinc and chromium. 39. Method according to sub-claim 38, characterized in that said inorganic layer consists of a solid phase. 40. Method according to sub-claim 38, characterized in that said inorganic layer consists of a liquid phase. 41. The method of sub-claim 38, characterized in that said outer non-organic layer is constituted by a vapor phase. 42. The method of sub-claim 39, characterized in that said inorganic layer is further removed. 43. Method according to sub-claim 42, characterized in that said metallic reproduction is turned. 44. A method according to sub-claim 43, characterized in that said metal is silver and in that said toning is effected by hydrogen sulfide vapor. 45. Method according to Ja sub-claim 42, characterized in that the operations of removing said interaction product and said non-organic layer are carried out simultaneously by momentarily bending said element after exposure to radiation, this around an organ. support (50). 46. The method of sub-claim 40, characterized in that said non-organic layer is removed. 47. Method according to sub-claim 46, characterized in that said metallic reproduction is turned. 48. Method according to sub-claim 47, characterized in that said metal is silver and in that said toning is effected by hydrogen sulphide vapor. 49. The method of sub-claim 46, characterized in that the operations of removing said interaction product and said non-organic layer are carried out simultaneously by momentarily bending said element after exposure to radiation around a section member. circular (50). 50. The method of sub-claim 41, characterized in that said metallic reproduction is turned. 51. The method of sub-claim 50, characterized in that said metal is rare and in that said toning is effected by hydrogen sulfide vapor. 52. The method of sub-claim 41, characterized in that the operation of removing said interaction product is carried out by momentarily bending said element after exposure around a member (50) of circular section. 53. A method according to sub-claim 38, characterized in that the material of said inorganic layer is selected from a group comprising metal halides, metal sulphides, metal arsenides, metal selenides, tellurides of metal and mixtures thereof. 54. The method of sub-claim 38, characterized in that the material constituting said inorganic layer is selected from a group comprising arsenic trisulfide. arsenic pentasulfide and angels thereof. 55. The method of claim I, (fig. 9-18), for establishing a relief image using a multilayer element sensitive to radiation and comprising several pairs of superimposed and adherent transmitting layers. said radiation, each of said pair of layers comprising two adherent layers (112, 114) made of different materials capable, when exposed to said radiation, to interact to form an interaction product (132) of which the composition and physical characteristics differ from those of said materials, characterized in that radiation defining an image is applied to the first of said pairs of layers so that said radiation partially penetrates beyond the first of said pairs of layers, this at a depth which is proportional to the intensity of said radiation, this by forming zones in which the interaction product is formed at a depth depending locally on the intensity of said radiation and in that said product is removed interaction. 56. Method according to sub-claim 55, characterized in that the image formed by said radiation consists of an outline (136) of the relief image to be obtained and in that at least one of said pairs is removed. layers in the perimeter delimited by said contour so as to form a recessed surface (140) corresponding to said contour. 57. Method according to sub-claim 55, characterized in that the image defined by the radiation consists of an outline (136) of the relief image to be obtained and in that at least one of the pairs is removed. layers outside the perimeter of said outline so as to define a raised surface (142) corresponding to said outline. 58. The method of sub-claim 55, characterized in that said interaction product is removed by a chemical action. S9. Method according to sub-claim 55, characterized in that said interaction product is removed by mechanical action. 60. The method of sub-claim 55, characterized in that said interaction product is removed by sublimation by heating. 61. The method of claim I, (fig. 80-86), for establishing an offset lithographic plate using an element sensitive to radiation and comprising mainly three different layers substantially adhering to each other. others, the first of these layers being metallic (712), the second of these layers being of a material (714) capable, when exposed to said radiation, of forming an interaction product with said first layer, and the third of these layers being of a material (716) incapable of interacting with said second layer, said first layer easily allowing said radiation to pass, characterized in that an image formed by the radiation is applied to said first radiation transmitting layer for causing the selective and discontinuous formation of said interaction product (728), so that the parts of said first layer which have been selectively and discontinuously irradiated exhibit a ratio between hydrophilicity and oleophilicity which is different from that of the portions which have not been irradiated. 62. Method according to sub-claim 61, characterized in that said first layer is a metal belonging to a group comprising silver, nickel, copper, colombium, lead, iron, aluminum, zinc. , chromium and mixtures thereof. 63. The method of sub-claim 61, characterized in that the material of said second layer is selected from a group comprising metal halides, metal sulphides, metal arsenides, metal selenides, metal tellurides. , arsenic trisulfide, arsenic pentasulfide and mixtures thereof. 64. The method of claim I (Fig. 82) for establishing an offset lithographic plate using an element sensitive to radiation and comprising three different layers substantially adhering to each other, the first of these layers being metallic (712), the second of these layers being of a material capable (714), when exposed to said radiation, of forming an interaction product with said first layer, and the third of these layers being of a material (716) incapable of interacting with said second layer, said second and third layers being permeable to said radiation, characterized in that an image defining radiation is applied to said third layer to cause selective and discontinuous formation of said interaction product (728) at the boundary between said second and third layers by selectively and discontinuously consuming portions of said interaction product (728). this first layer, so that the parts of this first layer which have been subjected to the reaction exhibit a ratio between hydrophilicity and oleophilicity which is different from that of the parts which have not been subjected to the reaction. 65. Method according to sub-claim 64, character ized in that said first layer is made of a metal belonging to a group comprising silver, nickel, copper, colombium, lead, iron, aluminum, zinc, chromium and mixtures thereof. 66. Method according to sub-claim 64, character ized in that the material of said second layer is selected from a group comprising metal halides, metal sulphides, metal arsenides, metal selenides, metal tellurides, arsenic trisulfide, arsenic pentasulfide and mixtures thereof. 67. The method of claim I, (fig. 84), for establishing an offset lithographic plate using an element sensitive to radiation and comprising three dissimilar layers substantially adhering to each other, the second of these layers being metallic (712), the first of these layers being of a material (714) capable, when exposed to said radiation, of forming an interaction product with said second layer, the third of these layers being of a material (716) incapable of interacting with said second layer, said first layer and said interaction product being soluble in a solvent and said second layer being insoluble in said solvent, characterized in that an image formed by the radiation is irradiated on said first layer to cause selective and discontinuous formation of said interaction product (728) at the boundary between said first and second layers by selectively and discontinuously consuming the portions said first layer, and in that said interaction product and said first layer are selectively and discontinuously dissolved in said solvent thereby exposing portions (736) of said third layer, the remaining portions (734) of said first layer. said second layer having a hydrophilicity to oleophyll ratio which is different from that of the exposed portions of said third layer. 68. The method of sub-claim 67, characterized in that the material of said second layer is selected from a group comprising metal halides, metal sulfides, metal arsenides, metal selenides, metal tellurides. , arsenic trisulfide, arsenic pentasulfide and mixtures thereof. 69. A method according to sub-claim 67, characterized in that the surface of said third layer which faces towards the second layer is roughened to increase the hydrophilicity and cause better fixation of said second layer. 70. Element according to claim II, characterized in that said first layer is a metal belonging to a group which comprises silver, nickel, copper, colombium, lead, iron, aluminum, zinc, chromium and mixtures thereof. 71. Element according to claim II, characterized in that the material of said second layer is selected from a group comprising metal halides, metal sulphides, metal arsenides, metal selenides, metal tellurides and mixtures thereof. this. 72. Element according to claim II, characterized in that the material constituting said second layer is selected from a group comprising arsenic monosulphide, arsenic disulphide, arsenic trisulphide, arsenic pentasulphide and mixtures. of these. 73. Element according to claim II (fig. 91-100), characterized in that it consists of a material sensitive to particle bombardment. 74. Element according to claim II (fig. 91-100), characterized in that it consists of a material sensitive to light. 75 Element according to claim II, characterized in that the geometric characteristics of said first and second layers are different. 76. Element according to claim II, characterized in that said first layer is arranged so as to adhere to a flexible sheet of a material belonging to a group comprising paper, cardboard, plastic. 77. Element according to sub-claim 76, characterized in that said second layer is a solid phase. 78. Element according to sub-claim 76, characterized in that said second layer is a liquid phase. 79. Element according to claim II, characterized in that it comprises several pairs of superimposed and adherent layers transmitting said radiation, each of these pairs of layers itself consisting of a first and a second adherent layer. 80. Element according to sub-claim 79, characterized in that the material of the first layer comprises at least one metal belonging to the group comprising silver, nickel, copper, colombium, lead, iron, aluminum, zinc and chrome. 81. Element according to sub-claim 80, characterized in that the material of the second layer is selected from a group comprising metal halides, metal sulphides, metal arsenides, metal selenides, metal tellurides. and mixtures thereof. 82. The element of sub-claim 80, characterized in that the material of the second layer is selected from a group comprising arsenic monosulfide, arsenic disulfide, arsenic trisullide, arsenic pentasulfide and mixtures of these. 83. Element according to claim II, characterized in that it comprises a substrate and an adherent layer of a material consisting of a mixture of arsenic and sulphide, said layer having first zones whose chemical and physical characteristics are different from those of the second zones. 84. Element according to sub-claim 83, characterized in that the hydrophilicity and oleophilicity ratios of said first zones are different from the hydrophilicity and oleophilicity ratios of said second zones. 85 Element according to sub-claim 83, characterized in that said first zones and second zones exhibit differences in solubility in a predetermined solvent. 86. Element according to sub-claim 83, characterized in that said inorganic layer is made of arsenic trisulfide. 87. Element according to sub-claim 83, characterized in that said inorganic layer is made of arsenic pentasulfide. 88. Object according to claim III, characterized in that it is photoresist and comprises arsenic and sulphides. 89. Object according to sub-claim 88, characterized in that it comprises arsenic trisulfide. 90. Object according to sub-claim 88, characterized in that it comprises arsenic pentasulfide. 91. Object according to claim III, characterized in that it consists of an electrical resistance. 92. Object according to claim III, characterized in that it consists of an electric capacitor.